July 4th, 2012 I threw a leg over the first Marauder prototype and instantly knew I was on to something fun. 10 years later, countless prototypes, many rides under my belt, and I’m still at it, nose to the trail refining the Marauder. This latest iteration is a lesson in progression and radically different from the one I built in 2012. The spirit is the same. The essence is still true to form and all about having fun out on the trail. Basically it’s my attempt at creating a big BMX bike for the trail.
As all things in mountain biking have become longer, lower and slacker, so has the Marauder. I won’t lie: I’m all in on the concept of forward geometry. You can carve harder. Lean harder. And just plain go faster. Ironically, I’ve seen video of myself lately and I’m definitely slow or the camera is making what I feel is fast way slower… Fast or slow, I’m after fun and last I checked fun doesn’t have a speedometer. However, one thing I started to notice with the last prototype: As I was able to ride a bit harder, faster, and more stable throughout due to radical changes in geometry that is forward geo, I started to notice just how harsh the rear end began to feel. Granted, some carbon wheels have gotten incredible stiff. The bike I noticed this on and was most pronounced was the latest steel Marauder prototype I built for the ENVE show last year shown below:
This one isn’t all that much different than the latest prototype (other than one glaring point that it is steel). What’s most decidedly different about these two builds? Bottom bracket drop and chainstay length. Now in isolation, those two numbers are pretty standard fair. 2.25″ and 16.5″ respectively – technically 16.4 slammed and when tensioned with a 32x20t SS setup, CS length lands right at 16.5″ / 419mm. But man are those ENVE wheels STIFF. Like teeth chattering stiff. On smooth buff trail, they sing. But the trails here in NH are anything but buff if you’ve had the chance to have ridden any lately. So stiff wheel + short rear end + relatively moderate drop + long front center = less than ideal ride characteristics. It was more pronounced than this build which was built in 2018. Now everything between these bikes is about the same with the exception of the wheels. I built the Nox wheels which are 32 spoke and decidedly stiff but not as stiff as those ENVE’s which are 28 hole. The one piece of the missing link is head tube angle which alters front center across all of these 3 builds due to the fact that they are built around my fit measurements and share the same basic cockpit length (center of the bars to the tip of the saddle). So keeping cockpit the same, a change in head tube angle results in a lengthening of front center while chainstay length, or rather rear center remains the same. I had been running a 67° HT angle but had slackened it to 66° in these latest two prototypes. But this has been the sticking point of progression I’ve been taking more note of.
Here’s what I’ve observed and I suppose here’s my theory of what is going on: As front center has grown, the timing between the front wheel hitting an object and the rear wheel proceeding to hit that same object is lengthened. The shorter the distance, the quicker in succession those two hits are in relation to one another and what the rider will feel. The longer that distance, and the time you feel those hits will be longer in succession. There’s a caveat here in both scenarios: The front wheel has a suspension fork attached to it. The rear does not. So that shorter wheelbase bike will tend to skip across that hit at speed. Hits in short succession and that gets pronounced to a degree where control and stability are compromised resulting in twitchy handling. With those two points lengthened (front axle center and rear axle center), those hits come a bit more spread out and get smoothed out to a degree. But what I’ve noticed is there’s a tipping point where at speed on rough terrain which NH is apt to have, that second hit can be more pronounced because of the lengthened distances between axle centers. Yes, I’ve got more traction, control and composure, but holy cow am I getting beaten up down the trail when it gets rough due to that short rear end in combination with a long front end and stiffer than stiff wheels. Yes, you can tune some of this out with tire pressure changes and a properly set up fork but those changes in pressure started to straddle the “now I don’t have enough tire pressure” in other situations (think carving turns where you’re really weighting the front tire and pushing on the pedals) and all the tuning in the world of the fork doesn’t make up for the fact that the rear end is decidedly not suspended.
So back to the drawing board and here’s the 3, well 4, numbers I changed:
HT Angle: 66° (previously 67° on the 2018 Ti prototype – the Steel prototype from 2021 was 66°)
BB Drop: 2.5″ (every single mountain bike I’ve built to date has been 2.25″ – I fiddled with this early on and stuck with that drop number ever since the 2012 prototype)
CS Length: 16.9″ (Previously 16.4″ on all SS prototypes)
Cockpit Length: 20.75″ (Down from 21.5 and 21.75″ – my FS is currently running 20.5 and I may even change that too with a push of the saddle forward a bit)
GASP. You read that right – I lengthened CS length. In a world where there was a p!ssing match to see who could have the shortest chainstays no less. And I shortened my cockpit. And I increased bottom bracket drop. Fit wise, I wanted to try a more upright stance as I’ve been really digging it on the Snakedriver FS prototypes which are 20.5″, which effects reach and front center naturally. Bottom bracket drop was increased as this effects handling and steering characteristics to a degree. It also drops rider center of gravity too and in my case, it reduced saddle to bar drop. Last is that chainstay length. My thinking here is thusly: If lengthening front center has aided to more control and composure, but keeping rear center as is has given the bike a more harsh ride characteristic, (read hits are more pronounced), perhaps lengthening CS length will dampen those pronounced hits. Basically: As front center changes, rear center must follow. A bit of logic to the 16.9″ number: The next jump in chain tension madness is 2 links. When tensioning a 32x20t, those 2 links equate to a length 17″ / 431.8mm. If I build to 16.9″, that keeps the sliders basically slammed in the slots of the hooded sliders and I get the maximum amount of adjustability and room to grow as the chain stretches. Make sense? Nothing is never done without a reason. Not to mention Eastern Woods Research chainstays were 15.9″. The Golden Mountain Bike Ratio’s were speaking to me.
The other updates included moving from a 130mm fork to a 140mm fork. I wanted to try a bit more travel but more travel equals a longer axle to crown length which means that front end can be slackened (hence 66°) without the front end getting too low. Bar height is incredibly important and its relation to the pedals equates to a lever. The fit and relationship of those numbers are important as is the distance between your bars and saddle. The two are important but balancing them to achieve attributes you’re after when seated or standing out of the saddle with saddle slammed requires a bit of voodoo and witch-wanding to get the right balance so you’re comfortable while climbing (and the bike still can climb) or jibbing and descending. The other update is the addition of a printed yoke.
This was printed by Silca and made in the USA. That’s something I’m quite proud of and the partnership has been wonderful. Their prints are some of the tightest and cleanest I’ve had in the shop. And that yoke now gets me lots of tire clearance in relation to chainring clearance and I can now ditch the 12×157 rear end with a 84mm bottom bracket to Boost 12×148 and a 74mm T47. So no more sheered off drive side cups either. Here’s a look at that in process:
And that 2 1/16″ Ti T47. Boy did that thing weld up SWEET. Keeping those T47’s round is a challenge and Mark at Paragon did a great job with these thicker T47’s shells in Ti.
Another tweak was changing the location of the dropper port from around 10 o’clock to 6 o’clock. This just makes cable routing WAY smoother and thanks to designing around a Salsa port stock part, moisture and muck stay the heck out.
One last change was seat tube angle. For years I’ve been building around an actual ST angle of 72° which resulted in an effective ST angle of about 74-75° (the curve in the seat tube kicks if forward by a good margin, so slackening it keeps it akin more to a 73° actual seat tube angle). But I steepened it by a degree so actual ST angle is 73° resulting in an effective angle of 76°. This subtle change also helped keep me centered IN the bike when seated and kept that weight distribution a tad more forward during climbs when the terrain steepens. Again, these are subtle changes, but subtle is the name of the game. It’s a game of numbers with geometry and performance and their relationship to one another from tip to tail of a bike. Nothing can be considered on its own. All of these numbers play off of one another. I can’t stress that enough.
So lots of subtle, small, incremental changes but those add up to big results out on the trail. Most notably here is overall with these changes, I’ve been able to rein in and reduce wheelbase so the latest bike is just about identical in wheelbase to the Ti prototype from 2018 which decidedly rode much better if comparing the 2021 steel prototype. But again, a lot has been changed between those two axle centers and the distribution of front and rear center has decidedly been altered between the two bikes. Which if I trust my hunch, would have noticeable results out on the trail. And I can confirm that all of these subtle tweaks geometry wise make big changes in ride characteristics out on the trail:
First the bike is composed and sure footed at speed. It climbs well. It descends equally as well and wants to seek a straight line but that’s not to the detriment of nimbleness in tight singletrack or twisties. Remember, long, low and slack you LEAN the bikes of the 21st century more than you steer the bikes of the 90’s with 120mm stems (which will bring me to another interesting point here in a minute). It’s basically a well performing, fast and fun trail bike. But what really changed was just how smooth the overall ride quality became now that I actually paid attention to front and rear center distribution. Lengthening the rear center (aka chainstay length) while dropping the bottom bracket a touch sunk me a little lower in the bike but stretched out and distributed some of that overall wheelbase to the rear of the bike. So those hits were no longer as pronounced (nothing changed – I’m running the exact kit of components between bikes). Here’s some of that tire clearance for you:
The other relationship I’ve mentioned is the distance or rather the measurement between your hand positioning and your pedals (which are basically a lever), but the other one is hands in relation to the axis of steering. On the bikes of the 90’s which have stem lengths anywhere from 90-130mm+, your hands are in front of the axis of steering while the center of the bars is in front of the bottom cup of the head tube. So you essentially “push and pull” the front tire to the left or the right. But with a short stem and longer front center making up for what was removed when you reduce stem length, which is typically in the 30-50mm range (I’m running a I9 A318 30mm Stem for the record), your hands are now in-line with or very close to being in-line with the steering axis while the handlebar clamp area is just behind the steering axis as it passes through the lower head tube center point. This markedly changes the dynamic of how you’re steering & handling your bike. And if you’re running a wider bar setup, you’ve got a heck of a lot more leverage with a 780mm+ bar than say a 580-600mm bar of the 90’s. With that short stem, steering input is much more direct which does not require a lot of rider feedback to how the bike is tracking. To illustrate this dynamic, see the image below. Image to the left is a 90mm stem with a 69° HT angle. The image to the right is the current bike with a 30mm stem and 66° HT angle. Keep in mind there’s some perspective differences between both photos, but that still does not take away from the fact that you can see where my hands are in relation to the steering axis and whether they are in front of or behind that axis. Also notice the distribution of the two triangles the relationship produces from hand position to ground contact points. This isn’t an exact science here using the actual prints (note its even more pronounced) but rather to illustrate this with images of two actually different bikes.
What all that translates to is more composure, more stability and less rider input required with the bike sporting the 30mm stem / 66° HT angle vs more twitch and more rider input required of the bike sporting the 90mm stem / 69° HT angle. You can also see just how much difference in bar height there is which has a lot to do with handling out on the trail and ease of being able to pick up and throw the bike around. Also note that distribution of stem length and how that effects the distances associated as you reach the ground (Readers Note: I’ve gone past the tire contact patch to illustrate this disparity on purpose – but where those meet up and where trail resides is in dotted lines).
All of this has made a world of difference in handling and performance. And since building this bike and putting it through its paces these past 6 or so months, I’ve immediately started to implement these changes to client bikes. So already the progression in my own bikes is being translated over to clients bikes. But what’s next? Yoke refinement. Although in its current form, the yoke is a tad less stiff than I’d like it to be. So I’ve already gone back to the drawing board and had Silca print me new samples, shown below in a side by side comparison:
This also has a stiffening “strut” through its core in addition to a much more refined form and how the socket is designed:
I’ll continue to put this bike through its paces. I’m quite pleased with how far the Marauder has come since 2012. Here’s the Flickr album for this latest build for those who want to see more of the process and more shots of the build (both clean and muddy!). And yes, I’ve been working on a post regarding the last two prototypes of the Snakedriver FS build and how that has been progressing. There’s much more to talk about and its been taking me some time to get it all down. But for now, I hope you’ve enjoyed a peek inside my process to where I’ve been, where I am and where I’m headed with the Marauder.
Progression
July 4th, 2012 I threw a leg over the first Marauder prototype and instantly knew I was on to something fun. 10 years later, countless prototypes, many rides under my belt, and I’m still at it, nose to the trail refining the Marauder. This latest iteration is a lesson in progression and radically different from the one I built in 2012. The spirit is the same. The essence is still true to form and all about having fun out on the trail. Basically it’s my attempt at creating a big BMX bike for the trail.
As all things in mountain biking have become longer, lower and slacker, so has the Marauder. I won’t lie: I’m all in on the concept of forward geometry. You can carve harder. Lean harder. And just plain go faster. Ironically, I’ve seen video of myself lately and I’m definitely slow or the camera is making what I feel is fast way slower… Fast or slow, I’m after fun and last I checked fun doesn’t have a speedometer. However, one thing I started to notice with the last prototype: As I was able to ride a bit harder, faster, and more stable throughout due to radical changes in geometry that is forward geo, I started to notice just how harsh the rear end began to feel. Granted, some carbon wheels have gotten incredible stiff. The bike I noticed this on and was most pronounced was the latest steel Marauder prototype I built for the ENVE show last year shown below:
This one isn’t all that much different than the latest prototype (other than one glaring point that it is steel). What’s most decidedly different about these two builds? Bottom bracket drop and chainstay length. Now in isolation, those two numbers are pretty standard fair. 2.25″ and 16.5″ respectively – technically 16.4 slammed and when tensioned with a 32x20t SS setup, CS length lands right at 16.5″ / 419mm. But man are those ENVE wheels STIFF. Like teeth chattering stiff. On smooth buff trail, they sing. But the trails here in NH are anything but buff if you’ve had the chance to have ridden any lately. So stiff wheel + short rear end + relatively moderate drop + long front center = less than ideal ride characteristics. It was more pronounced than this build which was built in 2018. Now everything between these bikes is about the same with the exception of the wheels. I built the Nox wheels which are 32 spoke and decidedly stiff but not as stiff as those ENVE’s which are 28 hole. The one piece of the missing link is head tube angle which alters front center across all of these 3 builds due to the fact that they are built around my fit measurements and share the same basic cockpit length (center of the bars to the tip of the saddle). So keeping cockpit the same, a change in head tube angle results in a lengthening of front center while chainstay length, or rather rear center remains the same. I had been running a 67° HT angle but had slackened it to 66° in these latest two prototypes. But this has been the sticking point of progression I’ve been taking more note of.
Here’s what I’ve observed and I suppose here’s my theory of what is going on: As front center has grown, the timing between the front wheel hitting an object and the rear wheel proceeding to hit that same object is lengthened. The shorter the distance, the quicker in succession those two hits are in relation to one another and what the rider will feel. The longer that distance, and the time you feel those hits will be longer in succession. There’s a caveat here in both scenarios: The front wheel has a suspension fork attached to it. The rear does not. So that shorter wheelbase bike will tend to skip across that hit at speed. Hits in short succession and that gets pronounced to a degree where control and stability are compromised resulting in twitchy handling. With those two points lengthened (front axle center and rear axle center), those hits come a bit more spread out and get smoothed out to a degree. But what I’ve noticed is there’s a tipping point where at speed on rough terrain which NH is apt to have, that second hit can be more pronounced because of the lengthened distances between axle centers. Yes, I’ve got more traction, control and composure, but holy cow am I getting beaten up down the trail when it gets rough due to that short rear end in combination with a long front end and stiffer than stiff wheels. Yes, you can tune some of this out with tire pressure changes and a properly set up fork but those changes in pressure started to straddle the “now I don’t have enough tire pressure” in other situations (think carving turns where you’re really weighting the front tire and pushing on the pedals) and all the tuning in the world of the fork doesn’t make up for the fact that the rear end is decidedly not suspended.
So back to the drawing board and here’s the 3, well 4, numbers I changed:
HT Angle: 66° (previously 67° on the 2018 Ti prototype – the Steel prototype from 2021 was 66°)
BB Drop: 2.5″ (every single mountain bike I’ve built to date has been 2.25″ – I fiddled with this early on and stuck with that drop number ever since the 2012 prototype)
CS Length: 16.9″ (Previously 16.4″ on all SS prototypes)
Cockpit Length: 20.75″ (Down from 21.5 and 21.75″ – my FS is currently running 20.5 and I may even change that too with a push of the saddle forward a bit)
GASP. You read that right – I lengthened CS length. In a world where there was a p!ssing match to see who could have the shortest chainstays no less. And I shortened my cockpit. And I increased bottom bracket drop. Fit wise, I wanted to try a more upright stance as I’ve been really digging it on the Snakedriver FS prototypes which are 20.5″, which effects reach and front center naturally. Bottom bracket drop was increased as this effects handling and steering characteristics to a degree. It also drops rider center of gravity too and in my case, it reduced saddle to bar drop. Last is that chainstay length. My thinking here is thusly: If lengthening front center has aided to more control and composure, but keeping rear center as is has given the bike a more harsh ride characteristic, (read hits are more pronounced), perhaps lengthening CS length will dampen those pronounced hits. Basically: As front center changes, rear center must follow. A bit of logic to the 16.9″ number: The next jump in chain tension madness is 2 links. When tensioning a 32x20t, those 2 links equate to a length 17″ / 431.8mm. If I build to 16.9″, that keeps the sliders basically slammed in the slots of the hooded sliders and I get the maximum amount of adjustability and room to grow as the chain stretches. Make sense? Nothing is never done without a reason. Not to mention Eastern Woods Research chainstays were 15.9″. The Golden Mountain Bike Ratio’s were speaking to me.
The other updates included moving from a 130mm fork to a 140mm fork. I wanted to try a bit more travel but more travel equals a longer axle to crown length which means that front end can be slackened (hence 66°) without the front end getting too low. Bar height is incredibly important and its relation to the pedals equates to a lever. The fit and relationship of those numbers are important as is the distance between your bars and saddle. The two are important but balancing them to achieve attributes you’re after when seated or standing out of the saddle with saddle slammed requires a bit of voodoo and witch-wanding to get the right balance so you’re comfortable while climbing (and the bike still can climb) or jibbing and descending. The other update is the addition of a printed yoke.
This was printed by Silca and made in the USA. That’s something I’m quite proud of and the partnership has been wonderful. Their prints are some of the tightest and cleanest I’ve had in the shop. And that yoke now gets me lots of tire clearance in relation to chainring clearance and I can now ditch the 12×157 rear end with a 84mm bottom bracket to Boost 12×148 and a 74mm T47. So no more sheered off drive side cups either. Here’s a look at that in process:
And that 2 1/16″ Ti T47. Boy did that thing weld up SWEET. Keeping those T47’s round is a challenge and Mark at Paragon did a great job with these thicker T47’s shells in Ti.
Another tweak was changing the location of the dropper port from around 10 o’clock to 6 o’clock. This just makes cable routing WAY smoother and thanks to designing around a Salsa port stock part, moisture and muck stay the heck out.
One last change was seat tube angle. For years I’ve been building around an actual ST angle of 72° which resulted in an effective ST angle of about 74-75° (the curve in the seat tube kicks if forward by a good margin, so slackening it keeps it akin more to a 73° actual seat tube angle). But I steepened it by a degree so actual ST angle is 73° resulting in an effective angle of 76°. This subtle change also helped keep me centered IN the bike when seated and kept that weight distribution a tad more forward during climbs when the terrain steepens. Again, these are subtle changes, but subtle is the name of the game. It’s a game of numbers with geometry and performance and their relationship to one another from tip to tail of a bike. Nothing can be considered on its own. All of these numbers play off of one another. I can’t stress that enough.
So lots of subtle, small, incremental changes but those add up to big results out on the trail. Most notably here is overall with these changes, I’ve been able to rein in and reduce wheelbase so the latest bike is just about identical in wheelbase to the Ti prototype from 2018 which decidedly rode much better if comparing the 2021 steel prototype. But again, a lot has been changed between those two axle centers and the distribution of front and rear center has decidedly been altered between the two bikes. Which if I trust my hunch, would have noticeable results out on the trail. And I can confirm that all of these subtle tweaks geometry wise make big changes in ride characteristics out on the trail:
First the bike is composed and sure footed at speed. It climbs well. It descends equally as well and wants to seek a straight line but that’s not to the detriment of nimbleness in tight singletrack or twisties. Remember, long, low and slack you LEAN the bikes of the 21st century more than you steer the bikes of the 90’s with 120mm stems (which will bring me to another interesting point here in a minute). It’s basically a well performing, fast and fun trail bike. But what really changed was just how smooth the overall ride quality became now that I actually paid attention to front and rear center distribution. Lengthening the rear center (aka chainstay length) while dropping the bottom bracket a touch sunk me a little lower in the bike but stretched out and distributed some of that overall wheelbase to the rear of the bike. So those hits were no longer as pronounced (nothing changed – I’m running the exact kit of components between bikes). Here’s some of that tire clearance for you:
The other relationship I’ve mentioned is the distance or rather the measurement between your hand positioning and your pedals (which are basically a lever), but the other one is hands in relation to the axis of steering. On the bikes of the 90’s which have stem lengths anywhere from 90-130mm+, your hands are in front of the axis of steering while the center of the bars is in front of the bottom cup of the head tube. So you essentially “push and pull” the front tire to the left or the right. But with a short stem and longer front center making up for what was removed when you reduce stem length, which is typically in the 30-50mm range (I’m running a I9 A318 30mm Stem for the record), your hands are now in-line with or very close to being in-line with the steering axis while the handlebar clamp area is just behind the steering axis as it passes through the lower head tube center point. This markedly changes the dynamic of how you’re steering & handling your bike. And if you’re running a wider bar setup, you’ve got a heck of a lot more leverage with a 780mm+ bar than say a 580-600mm bar of the 90’s. With that short stem, steering input is much more direct which does not require a lot of rider feedback to how the bike is tracking. To illustrate this dynamic, see the image below. Image to the left is a 90mm stem with a 69° HT angle. The image to the right is the current bike with a 30mm stem and 66° HT angle. Keep in mind there’s some perspective differences between both photos, but that still does not take away from the fact that you can see where my hands are in relation to the steering axis and whether they are in front of or behind that axis. Also notice the distribution of the two triangles the relationship produces from hand position to ground contact points. This isn’t an exact science here using the actual prints (note its even more pronounced) but rather to illustrate this with images of two actually different bikes.
What all that translates to is more composure, more stability and less rider input required with the bike sporting the 30mm stem / 66° HT angle vs more twitch and more rider input required of the bike sporting the 90mm stem / 69° HT angle. You can also see just how much difference in bar height there is which has a lot to do with handling out on the trail and ease of being able to pick up and throw the bike around. Also note that distribution of stem length and how that effects the distances associated as you reach the ground (Readers Note: I’ve gone past the tire contact patch to illustrate this disparity on purpose – but where those meet up and where trail resides is in dotted lines).
All of this has made a world of difference in handling and performance. And since building this bike and putting it through its paces these past 6 or so months, I’ve immediately started to implement these changes to client bikes. So already the progression in my own bikes is being translated over to clients bikes. But what’s next? Yoke refinement. Although in its current form, the yoke is a tad less stiff than I’d like it to be. So I’ve already gone back to the drawing board and had Silca print me new samples, shown below in a side by side comparison:
This also has a stiffening “strut” through its core in addition to a much more refined form and how the socket is designed:
I’ll continue to put this bike through its paces. I’m quite pleased with how far the Marauder has come since 2012. Here’s the Flickr album for this latest build for those who want to see more of the process and more shots of the build (both clean and muddy!). And yes, I’ve been working on a post regarding the last two prototypes of the Snakedriver FS build and how that has been progressing. There’s much more to talk about and its been taking me some time to get it all down. But for now, I hope you’ve enjoyed a peek inside my process to where I’ve been, where I am and where I’m headed with the Marauder.