nathbdp

87.0 inches

its pretty easy to push, but lots of stop and go on my pista.

macka_fat

your knees are fine. it's gunning it from a stop to make that gap in traffic that I'd be worried about.

9Rings

Your knees one fine day...

I Like Peeing

If you're running a brake on it and use it, I think you'll be in good shape.

trons

seems a little high to be practical... get/use a brake

goldenskeletons

your street gearing is higher than my track gearing.

i don't know what your riding style is like, but the potential to do serious damage is certainly there.

fischer, max

i think it depends heavily on where you ride, how much you have to climb, and like these gents said, whether you run a brake. 87" is a ratio over 3:1, and if you're riding brakeless or climbing much, i think there's a good chance you might cause some knee damage.

I Like Peeing

I ride 69 gear inches, dude. If he wants to fly around on 87, that's fine by me... hope he always uses a brake instead of backpressure to slow down.

Aeroplane

Goodbye knees. Get a bigger cog, pronto, if not sooner.

DooDooBus

I live in Atlanta and run something like 88 (52/16 170mm cranks) and my knees feel fine. It sucks in stop and go. I run more lights, cut lanes more because it sucks to stop and start. Lots of people here run bigger gears then I see in other citys but as soon as I can I'm going down to a 48 on the front.

Revolution Smmr

wow

lvleph

Nice use of the challenger explosion.

fetch

i say spin for teh win?

roadfix

it depends on the knee

piwonka

i run anywhere from 73-75 inches...i just recently thought about switching to 50/17 from 50/18..that's going from 73 to 77 inches. yes, 77 inches...about as high i as i would go, i do have to climb some hills, i have to backpedal to stop and my knee hurt this morning for some reason, (with 73 inches)...a crazy tropical storm rolled in and i shortly therafter got drenched...maybe that made my knee hurt...i don't know.

i wouldn't run 87 inches...some guy here runs 50/14 on the street..i don't even know what that is except crazy and stupid...i tried to sell him my 19t cog out of my bag but he declined.

gfrance

Asking for trouble, or at the least, asking for frustration. I personally can't imagine getting that up to speed only to then have to bring it down again, over and over at all intersections. And I run thru lots of intersections. It's all about the spin and a comfortable cadence. With that size gear, you'll be in such a low cadence, grinding it out for most of your ride, unless you're either on the track, or on wide open roads. Go for comfort (not ego).

Re-Cycle

80.5" 49x16 brakeless at the moment makes me miss 48x17 with a brake

... don't do it

operator

Even supermans knees would explode.

mathletics

Do it for a while and then drop down to something reasonable. You'll feel way more in control, though you won't be able to hit 40mph so easily.

MrCjolsen

Mashing isn't so much a function of gear inches, but rather low rpms. Ideally, your gearing should have you spinning at 90-100 rpms at the speed you can maintain for the distance you wish to go.

87" is 23-26 mph at 90-100 rpms. If that were my average speed on my 14 mile commute, then I'd use that gear. But it's not. My speed is more around 18-19 mph which means I need something around 70".

If you normally ride 23-26 mph, the 87" won't hurt your knees. But danger lurkes if you generally ride slower than that.

andre nickatina

49x16 is perfect for bombing hills! Not the best on coming back up, but oh well... I'm 49x17 right (75 gear inches) and it's just about perfect, about the best all-around gearing I've found for street riding.

If the OP lives in a flat town with no wind, I don't see why not. Mashing that gear through a major headwind sounds like more than enough to make me want to get off my bike and walk, though.

Best bet: leave the 87" for the track, flip the wheel around to something like 70-80" for the streets.

dutret

Even if you do ride that fast unless you never have to stop, start or climb you're not going to be ok. 87 is a stupid gear for anything other then a race or perhaps a group ride.

fischer, max

yeah, and why would you even want a gear that high for the street?

Knickers

49:14