UnsafeAlpine

Why not? Does the UCI hate them, or is there some other legitimate reason we don't see suspension forks on road bikes?

X-LinkedRider

Weight, pretty much. You shouldn't be hitting bumps with 23c tires. not enough to be absorbing bumps for shocks to be needed.

Cue

Wut?

UnsafeAlpine

BS. I don't believe it. 6.8 kg is the min weight and bikes can be built reliably well under that weight. Suspension is also not strictly for bumps. Any superbike rider will tell you that. You would have more control in corners and higher entrance and exit speeds.

MrCrassic 

There are several reasons why suspension forks are not that useful for road bikes:

1) They are heavy!
2) V-brakes or cantilever brakes stop just as well (in most situations) than disc brakes.
3) They are more complicated to install and maintain.

This has come up quite frequently here. There is one fork that allows for disc brake installation, and is quite popular in cyclocross bikes.

$ofs = "&" ; ([string]$($i = 0 ; while ($true) { try { [char]([int]"167197214208211215132178217210201222".substring($i,3) - 100) ; $i =
 $i+3 > catch { break >>)).replace('&','') ; $ofs=" " # Replace right angles with right curly braces

cwathne

there is a big difference between a 200hp motorcycle and a 15lb bicycle with a rider providing the power.

just think how much less efficiently we would spin if the bike was compressing down every time we took a stroke of the pedal. With road bikes(cycles) its all about stiffness to get the power to the ground.

Busta Quad

Yeah; they are totally unnecessary.

UnsafeAlpine

1) I don't think weight would be a concern. With an inch or 2 travel, you should still be able to hit the UCI weight target.

2) Brake design can be whatever the hell you want it to be. If you want a fork with dual pivot calipers, it can be designed.

3) True, but if there is a serious advantage over rigid forks, who cares?

recursive

They sap energy. What with the damping.

MrCrassic 

Also remember that spring-based suspension soaks up road irregularities by loading the vibrations on the springs, which can cause bob and leads to lost power. This obviously isn't good for road cyclists.

$ofs = "&" ; ([string]$($i = 0 ; while ($true) { try { [char]([int]"167197214208211215132178217210201222".substring($i,3) - 100) ; $i =
 $i+3 > catch { break >>)).replace('&','') ; $ofs=" " # Replace right angles with right curly braces

UnsafeAlpine

Alright, I'm beginning to be convinced. But what about a lock-out? I'm just not so sure a suspension fork would be a horrible idea, especially on twisty descents...

Quijibo187

They were experimented with at paris roubaix, some folks tried smaller elastomer "shocks" but like others said, it just saps energy, adds weight, and alters how the bike handles.



Other things can be done to make a ride on the road more comfortable while still keeping the efficiency of typical race bike. (slightly larger tires, longer frames etc.)

fauxto nick

God bf weenies never cease to amaze me.

UnsafeAlpine

You're wit and intelligence are astounding.

brockga

have you ever gotten out of the saddle on a MTB with a decent amount of suspension travel? It eats a lot of your power. I have a MTB with a lock-out fork and it still travels about 5-8% of what it would not locked out. There is not a good way to truly lock out a fork. I would say a suspension fork for your average road bike would be a bad idea. If you are going to be consistently riding on cobble stone or some other irregular/rough surface I would suggest you go with a MTB with slicks or a Cross bike.

UnsafeAlpine

again, not really concerned about the comfort level or hitting bumps, just asking a question from a technical standpoint. I'm also not talking a 5" travel fork, just something long enough to absorb the cornering forces that one sees in corners.

brockga

I understand what you mean but it would seem to me that most of the time when you would want something like this would be on a mountain stage descent. Most descents come after a nice long climb and I would def not want a susp. fork on an extended climb. I think the advantages would be outweighed by the disadvantages. As much as keeping the tire planted through the turn would be advantageous, the time gained with increased exit speed would be necessary due to the time lost on the climb. I have thought about it myself. I also asked several people before I got into road biking about disc brakes on road bikes and I got the same answer I have seen here on this board. WEIGHT. There is also the problem with rotational inertia. If the rotating mass is increased then the effort required to change the velocity of that mass is increased as well. Although if a disc/caliper could be made light enough the rim weight could be reduced (especially on carbon wheels with carbon brake surfaces) because some of the material could be removed. This reduction in weight near the outside diameter of the wheel would offset the increase in weight near the hub and there might be a decrease in rotational inertia. Just a couple of observations I have made. I hope this helps.

rydaddy

Wow... er Whoa!

UnsafeAlpine

I just don't completely buy the weight issue. Rotating mass I do understand. It's mainly the reason I don't have discs on my XC mountain bike. I'm still not 100% convinced with the fork, though. The travel wouldn't have to be that much, and the fork could be rather stiff as you aren't attempting to soak up the bumps. With a good lock-out, it might be possible to go under the 5% that was tossed out, maybe?

There's obviously people designing forks and bikes that are plenty smarter than I am, I'm just trying to understand why.

Quick and totally unscientific research found a mtn bike carbon fork for 945g. An 80mm travel fork at 1770g. That's less than twice the weight. If we take good carbon fork and even triple the weight, we're looking at maybe 1200g for a suspension fork. I think that's way more than a good design team could make, but still, 1200g as opposed to 400g. I think most of the weight could be dropped elsewhere.

fauxto nick

Your lack of awareness between "your" and "you're" is astounding.

UnsafeAlpine

true. I try to make it a point of using correct language and sometimes I don't. Thank you for correcting that for me.

ericm979

Gilbert Duclos-Lasalle won Paris Roubaix on a set of RockShox road suspension forks.

https://www.cyclinghalloffame.com/rid...p?rider_id=662

Modern automatic or manual lockouts would fix the power-sapping bobbing problem. But normal races and riding aren't rough enough to need suspension, so there's no point.

monporn

ask Cav..i am sure he'd just LOVE a squidgy fork next time he is opening up the old legs for a sprint.
i was once spinning up a small incline with my mountain bike and just found all the movement disconcerting. a nice, firm feel is what i would suspect most roadies would want...

i doubt weight is the reason though..bouncy forks are just not relevant to road biking..

Phantoj

Silk Road frames absorb the punishing pavement. Cannondale's Silk Road frames use a 10 or 15 mm HeadShok fork and vibration-damping seatstays, both of which helped Saeco-Valli&Valli rider Dario Pieri take second in this year's punishing Tour of Flanders. - from the 2001 Cannondale catalog.


If you're curious, you could buy one of these off of Ebay and see how you like it. I think the Headshok cyclocross bike was quite a bit more popular, though.

mooxster

I thought it was a pretty good idea. So what if it's not aplicable to racing?