's Forum Archives - General

Archive Home >> General(1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 )

MTB speed......good enough for racing???(9 posts)

MTB speed......good enough for racing???kingcobradv
Oct 2, 2003 3:21 PM
Thanks for the replies!
I have a moutain bike that weighs about 35 pounds with 1.95" knobby tires. Usually I ride with baggy shorts and a t-shirt. My time for 20K is about 35 minutes at best on a course with some uphills and criterium type of turns.

Me and my cousin did 65 K going at about 28- 32 km/h (we did it a couple times) most of the way this summer. His bike weighs about 40lbs and the tires are 2" (knobby tires). Also his bike has full suspension and mine has just a front shock.

We both dont use clipless or toeclips.

Can anyone predict how fast we can go with the same effort using a "high end" road bike with a bike jersey/spandex and clipless pedals?

Is there some sort of calculations for this? Me and planning on getting a road bike this winter for racing in the spring.....

re: MTB speed......good enough for racing???kingcobradv
Oct 2, 2003 3:28 PM
sorry for the grammer........ We are planing on racing criteriums/TT's this spring but we dont have a road bike yet.
Our time for the 65 K is 2:25 minutes and that includes a dozen traffic lights, sharp turns, hills and people getting in our way.

Any suggestions on where to get a good deal on a road bike?
2 minutes 25 seconds!!!Humma Hah
Oct 2, 2003 3:48 PM
Chuckle. 2 hours 25 minutes? That'd be better.

The world is full of good bikes, but NONE of them are found in department stores. And no bike, not even a $4000 carbon and titanium miracle of technology, is worth buying if it does not fit you. Go find a good shop that sells roadbikes, pay them to put you on a "fit kit", and find the right size. THEN go shopping.

If it were me, I'd look for a good used bike at a place like Trexlertown, PA (huge flea market this Saturday, won't be able to swing a worn-out chain without hitting a bargain). Race it a little, get a chance to meet some people, see and try some bikes, see what you like, and THEN fork over the money for a good one.
oops another typokingcobradv
Oct 2, 2003 3:55 PM
How competitive you will be will be strictly based on ...Humma Hah
Oct 2, 2003 3:41 PM
... how good the local competition is. In some areas, a fire-breathing amateur on a MTB can beat the local un-ranked wannabee roadies, maybe even hang with racers who are "Cat 5" (beginners, but serious enough to fill out a form). And I personally think it is great fun when the occasional MTBer shows up in baggies and a t-shirt on a MTB, and beats the roadies -- pretty rare, but great fun when it happens.

But generally, for long-distance pace, you can expect a roadbike has at least a 2.5 mph advantage, and for shorter racing distances, a roadbike may have up to about a 5 mph advantage, mostly based on better aerodynamics. If climbing is involved, you can also add 1-2 mph for the lighter weight.

I can testify to that ... my three bikes are a 44-pound fat-tired singlespeed cruiser and a comparably-geared 24-pound fixed gear roadbike, plus a 3x7 32-pound MTB. A century last weekend, compared to the same ride on the cruiser, showed the roadbike is almost exactly 2.5 mph faster, on average, at a long-distance pace. I can also testify that the roadbike is about 2 mph faster on climbs.

The MTB, with slick tires, is only about 0.6 mph faster than the cruiser's best performance over 20 miles.

Your bike is heavy even by MTB standards, even heavier than my porky Diamondback. Competitive bikes today are 23-25 pounds. Roadbikes are more likely around 18 pounds. That's a very noticable difference when climbing. On the other hand, high weight is not a bad thing in a fitness bike. Just don't try to race on it.

Here's a website with enough performance calculations to make your brain hurt:
We want to be able to go 40 km/h for 50 km on a road bike...kingcobradv
Oct 2, 2003 3:53 PM this possible if you convert our mtb time/effort to a road bike? (also add the tights/clipless)
I think you'll need to train for that speed ...Humma Hah
Oct 2, 2003 4:19 PM
... That's by no means an un-attainable goal, but if you're capable of 32 kph for 50-ish km, you'll probably pick up to about 36 kph by switching to a roadbike. Another 4 kph on top of that is going to take extra power, which means training, learning to endure some pain, learning to stay "in the drops". It won't come instantly, you'll have to work at it. Increasing from 36 to 40 kph is an 11.1% power increase. To achieve it will take (40/36)^3 of the power you deliver at 36 kph, or a 37% increase in the power you're used to putting out. You can probably do it, but you're gonna have to WANT this enough to train seriously.

Clipless pedals CAN improve power by about 15%, but might or might not help you. You have to train in them to learn to get the advantage. If the bike doesn't fit you well, they may actually hinder or even injure you. And if your speed is limited by your cardiopulmonary condition, the extra power they make available will do no good. Try them, but I'd recommend that professional bike fit first.

Tights won't make much difference, although they may make you FEEL faster. A good jersey CAN help, especially in hot weather, because it lets you perspire away heat MUCH better than a t-shirt.

The thing that will help the most is making your BODY, not your clothes, more aerodynamic. Get your back as parallel to the ground as possible and KEEP it there. And learning to do that comfortably is the biggest hurdle in making the transition from MTB to roadbike.
But you'll need to jump to 50km/h every lap for 15 seconds,Spunout
Oct 3, 2003 3:44 AM
and accelerate from 35 to 45 out of every corner. Racing isn't solely about sustainable speed (Okay, TTing is) but the changes in pace, keeping on your wheel, recovering, and doing it all again.

Anyone can make predictions but...config
Oct 4, 2003 3:32 AM're just going to have to get on that road bike and do it yourself and see how fast you can go. I think one guy said what you wanted to hear on the same post a couple days ago. You can hang and race with Heras and Lance and can beat most of us here on this board. All with baggy pants, hairy legs, regular pedals and 35 lb mountain bike with knobby tires - you're faasst!!