sp00ki

I'm buying a set of rollers next month, and will be purchasing an ultra cheap "track bike" ($75) for sole use with the rollers. I already have a trainer setup for doing resistance and sprint intervals, but wanted to use rollers specifically for improving high cadence form/aerobic condition on alternate days.
I'm thinking a very agile gearing will force me to do high rpm, and eventually improve my form on descents/all out sprints.
What gearing is too "agile" for rollers? I understand that part of the physics behind balancing on rollers is spinning your wheel, so i don't want it to be so low that the rollers are rendered useless, but i don't want it to be too high as to offer any resistance. I don't have experience on rollers w/a low gear ratio, so i'm kinda clueless as to how much the lower ratio will inhibit effective rolling. My TT bike is currently in pieces, so i'm thinking a good recommendation is my best bet to avoid swapping out too many chains/chainrings (time/money).

Anyone with experience have a suggestion?

lumenredundas

gear ratio doesnt really matter on rollers. there is no resistance so you can get to a high rpm no matter what. if you are really concerned with it get a road bike and play around with the all the gear ratios that are on it. that way you dont have to keep switching your rings and cogs on your track bike.

sp00ki

I could, but like i said-- my tt bike is in pieces (some of which i no longer have, i'm building it back up atm). I suppose i could try to find someone my size with a roadbike who'd let me borrow it, but the likelyhood of that happenning seems slim-ish.

So you feel that riding (for instance) 47/14 will offer no more resistance than riding 42/16 (on rollers)?
Can you possibly explain the physics behind how they work? I've only used rollers with a single ratio, and haven't spent enough time on them to figure out the science behind why they work (i was under the impression that the rate of wheel spin added to the stability and was the basis of their being feasible).

shasta

Have you ever tried spinning a wheel while you hold it by the axle? If you try to change its axis of rotation from vertical to horizontal it will fight you. The faster the wheel spin the wheel the more it fights you. When you are on the rollers this force helps the bike stay vertical.

I'm sure there is a fancy name for this principle but I don't know what it is. Gyroscope?

sp00ki

Yes, that's the impression i was under.
So assuming that's the case, how low a gearing is too low? Based on a discussion in a different subforum, i'm thinking 41/17 will be good start for what i'm looking for.
I'll probably go lower as my form at higher cadences improves.

dlandis

It would depend on how big the radius of the roller wheels is. Probably you are fine with that gearing though.

shasta

I just asked my friend who actually owns rollers and he says "If you are not experienced at riding on rollers you need to have a gear ratio over 3, or you need to put it in the hallway so you can grab the wall before you fall over"

I would just stick with your gearing and put the rollers near something you can grab onto just in case.

sp00ki

There are two support beams in my house just wide enough for the rollers that i plan on using until i'm comfortable. I've used rollers before, so i know what to expect.

Thx for the advice

Cynikal 

I assume that a larger gearing (read go faster) would be better for rollers. This should increase the gyroscopic forces keeping up upright. As I said, this is an assumption. I've only ridden rollers once.

sp00ki

agreed. that's why i'm looking for lower gearing-- to "force" myself to keep a higher cadence, which would in turn "teach" me better form at higher rpms. i use a trainer for intervals and resistance training; the rollers would be offering me something completely different altogether.

diff_lock2

You could ride outside with 60 gear inches...

Yoshi

It's called precession (often called gyroscopic force or gyroscopic stability). Precession actually isn't necessary to keep a bike upright on the road but on rollers I imagine it is.

captsven

This is a great way to use rollers in the winter months.

The gear you are looking for depends on you mostly. What kind of shape are you in? What is your average speed when you are in shape and during the winter months.

Jet-man

it totally depends upon which rollers you get - and how much air pressure you're running.

Kreitler dyno-mytes are a serious workout for anyone - w/o a Killer Headwind. Dyno-lytes aren't as tough as the 'mytes' but still will give you as good of a workout as you want - especially if you're running 25c or fatter tires. The big Kreitler drums offer little resistance, and along w/ a brand-x roller set, you can spin out any gear.

dookie

amen.

the widely repeated rumor that 'rollers offer no resistance' (a la lumenredundas) is bull****. the only point of reference i can offer is that 48x17 on 700x23 is plenty of gear on 3" rollers (dynolytes). you will not spin this gear on these rollers at a high cadence for any length of time. promise.

OP, how big are the rollers? is there any sort of resistance unit?

sp00ki

Not sure, i wasn't aware of different diameters=more/less resistance.
Since i use the trainer for resistance training (intervals, mainly) i'm looking to use the rollers strictly for cadence/form/aerobics training. I want something with a lower resistance in this case. I was trying to achieve this with lower gearing, but i suppose a larger drum diameter is what i'm after.
i was going to buy this:
https://www.performancebike.com/shop/...tegory_ID=4121
c/nc?

nathbdp

rollers are not for resistance, they are for cardio and form. get a trainer for resistance.

sp00ki

i'm totally hacking you over the internet right now.

kemmer

that's what he just said.

sp00ki

don't, it's a trap!

sp00ki

but seriously, pls recommend some large diameter jams.

Duke of Kent

I can drop my road bike down into the 53x12 and do intervals at 320 watts at around 110rpm., with the resistance unit NOT engaged.

Obviously, you CAN do intervals on rollers. Anyone who says you can't is full of it.

sp00ki

can you at least kinda read the thread before posting?

Devolution

I flip my track bikes over to their track gear on rollers. From 49x18 on the street to 49x16 on the rollers.

Duke of Kent

My point was that you need to OVERGEAR for the rollers, not undergear for them to simulate road conditions.

Otherwise you aren't training your legs to deal with the loads associated with riding outdoors. A high cadence means nothing if you can't deal with real life riding scenarios.