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Hillbilly Scientist
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Discussion Starter · #1 · (Edited)
I have a great Puegeot double butted, DBS, chromoly frame that I am building a frankenbike out of. It is a hybrid 1" head tube, etc. looking at the geometry of the frame, I have decided that putting a 26" fork and wheel w/80mm travel up front and a 700c wheel in the back the frame sits perfectly. What can I expect in terms of performance. Pros V cons. Something thing more than the usual "your bike will suck" would be nice. lol ;)
 

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I believe that the normal 69 combo (26 in back, 29 in front) is to give a "best of both worlds" effect. 29" wheels have greater rotational mass, hindering acceleration. At the same time, a 29" wheel approaches obstacles with a lower angle of attack, meaning it rolls over them easier. So, it would seem that, with a 26" up front and a 29" in back, you'd have relatively slower acceleration, and no easier time getting over obstacles. Perhaps this is a good idea if you find your rear wheel getting hung up on things, otherwise, I cant figure an advantage.

Hey, its worth a try, I figure the ol' schwinns had a tiny wheel up front for some reason ;)
 

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noMAD man
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Bicycles are extremely sensitive at the front wheel in terms of suspension and the ability to get the bike over obstacles. I believe this is primarily because of their relatively light weight. The rider is the main weight in the whole combo. If the front wheel gets over the obstacle, the rear will usually follow. If something hangs up the front wheel, the bike often stops and the rider doesn't. If something hangs up the rear wheel, you usually just lose momentum or stall.

You mention that your bike "looks" balanced. A 29'er wheel setup is fairly dramatic. Do you know exactly how much the 80mm fork raised the front compared to what was on there? The raised front and the 80mm of travel will help the 26" wheel in its attempt to keep up with the 29'er in rollover quality, but remember that since the front is more critical in this issue, I think there will be an odd imbalance with this setup. And remember, you're probably measuring how much the front end is raised at the fork's maximum extended length. What happens when the front end hits that obstacle and fully compresses the full 80mm, and that tall rear end is just sitting there waiting for somewhere to go?
 

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Hillbilly Scientist
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Discussion Starter · #4 ·
TNC said:
Bicycles are extremely sensitive at the front wheel in terms of suspension and the ability to get the bike over obstacles. I believe this is primarily because of their relatively light weight. The rider is the main weight in the whole combo. If the front wheel gets over the obstacle, the rear will usually follow. If something hangs up the front wheel, the bike often stops and the rider doesn't. If something hangs up the rear wheel, you usually just lose momentum or stall.

You mention that your bike "looks" balanced. A 29'er wheel setup is fairly dramatic. Do you know exactly how much the 80mm fork raised the front compared to what was on there? The raised front and the 80mm of travel will help the 26" wheel in its attempt to keep up with the 29'er in rollover quality, but remember that since the front is more critical in this issue, I think there will be an odd imbalance with this setup. And remember, you're probably measuring how much the front end is raised at the fork's maximum extended length. What happens when the front end hits that obstacle and fully compresses the full 80mm, and that tall rear end is just sitting there waiting for somewhere to go?
Thanks for the feedback. I've been testing the setup for the past day or two. Compared to a rigid fork on a 700c wheel this set up is better. Your prediction was correct, with a larger tire (26 X 2.10) in front and the 80mm of suspension I have'nt had any real problems getting over anything. The back wheel seems smoother and seems to give the rear what the shock gives to the front of the bike to a degree. Uphill and downhill seem to give a similar performance so is the bike ballenced by this set-up? I tried a 700c X 40 hybrid tire in the rear with a wienmann double walled DA-16 made of 6061-T6 aluminum. I can't explain it exactly but there's no drag and it really kicks out on packed dirt- not so great on loose gravel but not terrible. What I did notice is that the rear doesnt bang around as much on technical single track. As long as I keep that front wheel true the rear seems to follow flawlessly. Then just for the hell of it I put a 700c X 45 studded snow tire on the rear- big difference! great up hill and great downhill breaking and since it's not a big fat tire it's not all that much slower, makes up for the loss of traction. Talk about a frankenbike! Well anyway at least I'm good for next Holloween. LOL
 

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Hillbilly Scientist
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Discussion Starter · #6 ·
Davidcopperfield said:
Great outcome and I believe that if you put a 700c tyra up front it would even boost the rolloverability of the whole bike, wouldn't it? Just put 29er fork like 120mm TA and a fat meat and see what is gonna happen. The bigger the better :)
I had a 700c ( It's a 22" 29er frame) in front but for some reason the uphill was a little harder to get on top of. I felt like I was pulling the wheel off the ground. I need to do some more testing- It's hard not to be subjective in just a few runs.
 

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mnt bike laws of physics
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I do agree that a bigger wheel up front has more advantages than in the rear, but I mostly look at things from a full suspension standpoint.
If you like the geometry, then the bigger wheel in the back would give you a little of the advantage of rear suspension (to roll over stuff without stalling) without all the complexity.

Enjoy your ride!
 

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Hillbilly Scientist
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Discussion Starter · #10 ·
yogiprophet said:
I do agree that a bigger wheel up front has more advantages than in the rear, but I mostly look at things from a full suspension standpoint.
If you like the geometry, then the bigger wheel in the back would give you a little of the advantage of rear suspension (to roll over stuff without stalling) without all the complexity.

Enjoy your ride!
Exactly my point. A FS set up would be different, your right. On a hard tail though this set-up makes more sense than I thought it would. Cheers
 

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www.derbyrims.com
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CoalHillsMcKracken said:
Exactly my point. A FS set up would be different, your right. On a hard tail though this set-up makes more sense than I thought it would. Cheers
I like the out of the box thinking, it makes some sense for a hardtail. Kind of Extreme-XC!

Pics?
 

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Hillbilly Scientist
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Discussion Starter · #12 ·
derby said:
I like the out of the box thinking, it makes some sense for a hardtail. Kind of Extreme-XC!

Pics?
I'll have some pics up this weekend. :thumbsup: I took the snow tires off cause I did'nt want to ruin them. We get big winters up here in the Poconos and those things are expensive. It just feels kinda badass on dirt. Makes a little noise too. If it were'nt for this damn economy I'd just buy another one and use it all season. This autistic fascination with bikes is kill'in me in the wallet.
 

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Hillbilly Scientist
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Discussion Starter · #14 · (Edited)
"Submariner"?

I have 12 bikes. My main ride was a 26" standard wheel, hardtail set up. I have been giving it to my customers to ride. Same thing with my FS 69er. I just love this set up. The uphills are awesome. I prefer the steering on tech single track to the 69er. The geometry kind of reminds me of a submarine- blunt and thick in the front with a tapered rear end that cuts the follow up. Maybe we could call this set-up the "Submariner"?
 

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Recovering couch patato
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I contenst the idea that 29" front, 26" rear is the best placement of the 2.

As a rear, 29" has more performance traits, especially in a front suspended setup.
Most of the rolling resistance come from the rear wheel, climbing stability and traction, butt comfort, back fatigue, etc.

26" front wheels come in all kinds and sizes. There will be one of your choice. Sure, a 29"er will always corner better IMO, but most of the time you're propbably still pedaling in a straight line?

I think your setup is way original. I might do that to one of my left-over cross bikes. Bet it rides really well. What fork length was the Peugeot originally built for?
 

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Derailleurless
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treestan said:
it would seem that, with a 26" up front and a 29" in back, you'd have relatively slower acceleration, and no easier time getting over obstacles
I'd have to agree with Cloxxki on this, at first glance.

Up front, you lose the "endoproofness" of the 29" wheel, but the front end is easier to lift and is weighted lighter ('specially on climbs), so "roll over ability" isn't as big a deal.

In the rear, the 29"er really shines with me for its climbing traction. And the rear usually gets slammed into obstacles with more brute force / less tact that the front, making the greater diameter a plus.

Arguements focusing on slower accelleration of the rear wheel are a red herring. Both wheels need to be accellerated, never mind which one the chain drives. So it shouldn't matter if it's 69 or 96.
 

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Recovering couch patato
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Speedub.Nate said:
I'd have to agree with Cloxxki on this, at first glance.

Up front, you lose the "endoproofness" of the 29" wheel, but the front end is easier to lift and is weighted lighter ('specially on climbs), so "roll over ability" isn't as big a deal.

In the rear, the 29"er really shines with me for its climbing traction. And the rear usually gets slammed into obstacles with more brute force / less tact that the front, making the greater diameter a plus.

Arguements focusing on slower accelleration of the rear wheel are a red herring. Both wheels need to be accellerated, never mind which one the chain drives. So it shouldn't matter if it's 69 or 96.
How easy or hard a front wheel is to be lofted IMO depends mostly on suspension or not, BB drop, rear axle height and chainstay length. Adding 150g-225g to the front wheel will surely be felt, but not make a serious difference.

If the front of the bike is now taller than before, you'll have lost some effective reach. Perhaps almost time for a monster cross setup with a CX handlebar? :)
 

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Derailleurless
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Cloxxki said:
How easy or hard a front wheel is to be lofted IMO depends mostly on suspension or not, BB drop, rear axle height and chainstay length. Adding 150g-225g to the front wheel will surely be felt, but not make a serious difference.
I think you misunderstood me, but perhaps I should have written more clearly: "It's easier to loft the front wheel than the rear. In this respect, having the smaller wheel up front isn't necessarily a hinderence, and the larger, easier rolling wheel in the rear can be appreciated."

Howzat?
 
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