ultimate geo. for standing technical climb on rigid SS?
If a rigid single speed were designed with a goal of optimal performance on technical climbs when out of the saddle, what sort of geometry would it have? Suppose all other aspects of handling and design (cornering, descending, compliance, etc) were ignored and the focus was just on technical climbing prowess when out of the saddle. What would the bike look like? Short stays? Steep HT with long front center? maybe the other way around completely with long stays, slack HT and short front center? I don't have any idea so I'm asking here.
Last edited by head; 03-20-2013 at 06:58 AM.
Reason: typo, spelling
loooooooong back end would trump any other characteristic.
I gotta disagree with this. In my personal experience, I've found that I climb steep, rocky, technical stuff better with my sliders all the way forward on my Nimble 9, so around 16.25". I'm able to get the front wheel over obstacles easier, have plenty of traction (even with a Maxxis Ikon, not exactly the paragon of grip,) and it's very easy to slightly shift weight forward to get the rear over ledges.
A long rear triangle is helpful to keep the front end down on seated, low-geared climbing where drivetrain torque is high.
For me, the short chain stay, slack angle geometry works the best. Climbing on a single speed is in some ways easier, since weight shifts are done almost automatically, the short stays allow the bike to turn well,and the slack head tube angle stabilizes things on the down side. That last point is importand, since technical climbs often lead to technical descents.
I also have similar thoughts as sslos. Long back end SS's (like the Vassago I had) had issues keeping the rear from spinning going up steep climbs (plus it handled like a boat). Compare that to a Canfield Nimble 9, which has one of the shortest stays, which just powered up the same climb(s) with minimal spin and sliced/diced up techy parts. One thing I would change is the shorter front end and the slacker angle. I think it would be a bit more nimble for tech climbing if it had a bit steeper HTA and a slightly longer TT to combat front wheel wandering on the steeper parts.
Now, I'm not saying that I would change the geo, because on the other side of the hill, I prefer the slacker HTA. Above comment was strictly for standing climbs.
ok so maybe i forgot you may have to lift the front wheel sometimes... but if we are talking climbing smooth steep walls of dirt i stand by my argument.
Regardless of whether you lift the front or not, short rear ends work better. Dirt bikes and snowmobiles built for climbing do have looooong rear ends, but that doesn't necessarily translate over to bikes, especially SS. When you're climbing out of the saddle, you want that weight over the rear wheel. It's much harder to do on a bike with longer CS.
You can't deny the benefits of long stays for climbing, especially in the motorsport world... but I agree that it's maybe less of a necessity for something as light as a bicycle... We're not hammering hard enough for the rear wheel to want to pass the front one like it does on a dirt bike going up the steep stuff.
My Rigid SS has long stays, and it's super easy to climb on while standing, because it's easy to keep your weight centered enough to avoid spinning the rear or lifting the front. Once you stand up though, keeping your weight in the right spot is probably more important than the length of the chainstays... if you can stay centered on a short bike and avoid spinning the rear or lifting the front, you're getting the same benefits, plus the advantage of the 'flickability' of a shorter bike.
Where I think the longer stays become an advantage is in the transition between sitting and standing. My long-stay bike will stay planted with the front tire on the ground until my legs just can't do it anymore, and then I can switch to standing without spinning or lifting relatively easily.
My shorter-stay bike makes this transition more difficult. When I'm sitting and it gets hard and techy, the front tire wants to lift, and If I don't keep my weight in the exact right spot while I'm making that transition to standing, I'm going to spin the rear.
But once I'm standing, shifting my weight counteracts whatever chainstay length the bike has. The longer stays are just a bit more forgiving if I get sloppy.
You have no excuse for driving to work
(unless you don't have studded tires)
(no excuse for that either)
I don't know if it's the ultimate geo for all standing and grinding, but the Jeff Jones bike is the best balanced bike I've ridden for climbing out of the saddle. I never feel like I have to work real hard to shift my weight around to find the sweet spot. Might want to check Jeff's website for the specs. Longish stays, but the bike's geo is geared with a bias towards weighting the rear wheel.
I think the general rule of thumb is if you like to put your chest on your stem and climb seated and spinning then you're more apt to prefer a longer stayed bike. If you like to stand and grind, then shorter stays help keep your weight over the rear for traction. But that's just the general wisdom. Experiences will vary.
You're so cute internet tough guy. Noogie...Noogie...Noogie.
Short chainstays are much better than long for climbing standing up. You're more likely to lose traction and spin the rear wheel with long stays. Longish front center and fairly steep head angle with a lot of offset to get low trail. The front end will wander less when climbing this way.
Fisher made an elevated chainstay bike in the early nineties (?) that had 15" chainstays. Thing climbed like a monkey and descended like you would expect a bike with 15" chainstays to.
I actually find the Jones geo to be really well suited to standing climbing. Reasonably short chainstays, higher offset fork, slackish angles but not too slack and shorter front center to make up for the higher offset fork. Add in some high bend bars like mary or jones loops and you have a stand and grunt winner.
Another vote for the Jones here, climbs better than pretty much all other non-FS bikes I've ridden (not all SS though).
BB drop and wheelbase / front-rear centre balance may be more important than just stay length, slack head angle has --all to do with it, too slack makes slow speed handling a floppy-steering nightmare. I've failed on climbs because of front-end flop, but never because a bike was too steep / quick handling (descending on it may be hopeless though, so a neutral-stable front works well and quite a few bikes do that well without going silly-slack)
I'll +1 the Los on this. Assuming you want to stand the whole time, short rear ends are good. Steering geometry is going to be a matter of personal preference - *most* people will prefer steeper HTA and lower trail numbers for techy climbing but you can get used to a wide range of steering setups in that situation so unless you don't care about how the bike handles downhill at *all* I would not let how you want the bike to climb decide that. 71 vs 69 HTA is not going to keep you from cleaning stuff once you're used to how the bike steers - your legs and rear wheel traction and general technical ability are the limiting factors.
Higher than normal BB will generally be good too, since when standing it can be very hard to ratchet/time pedals. But once again, you're going to make tradeoffs for riding on the flat/DH stuff.
I'll have to agree with Los, Walt, and the others above. Shorter stays, a slightly higher BB, and slack but not too slack HTA seem to be what does it for me. On SS having traction and pedal clearance are huge.
Jabberwocky was the worst climber I've owned to date, I'll never own another long CS bike again. The Jones does lend to good standing climbing as well, really good balanced geometry. Luckily I knew exactly what worked best for me when I had my Stickel built and it murders everything else I've owned (rigid or suspended, up or down!).
"I ride to clear my head, my head is clearer when I'm riding SS. Therefore, I choose to ride SS."~ Fullrange Drew
ultimate geo. for standing technical climb on rigid SS?
I have better luck maintaining traction with shorter stays and I even try to make sure my chain is short, so my rear wheel is "slammed" forward. Shorter stems also help me keep my weight on the rear tire. As we all know, spinouts often equal failure.