MTB versus Racer

Ian Smith twisted the electrons to say:
Perhaps the chap in question was attempting to regain some fitness after
a long absence from cycling, and still had all the gear from last time?
Or he was just plain knackered from having overdone it that day? Plenty
of possibilities.

I once got overtaken by an MTB, whilst riding a recumbent downhill! My
excuse is that I was knackered after a long ride ... and I'm sticking to
it!
--
These opinions might not even be mine ...
Let alone connected with my employer ...

Ian Smith wrote:
Only
issue is lower and wider step gearing than typical for road, but I
haven't become fit enough to run out of gears yet. Hopefully that'll be
remedied before too long. :-)

That's interesting. My last MTB (slicks) had 21 gears with top being
42/12. That wasn't a high enough ratio for me. I now have a similar
machine with 24 gears and top is 42/11. I have fat off-road tyres on
this and I estimate it's one full gear harder to push than the old bike
(despite being a bit lighter). Now, I find top gear is fine - this might
change when I put slicks on.

Happi

Andreas Schulze Bäing wrote:
On Sun, 09 Aug 2009 15:18:07 +0100, Happi Monday wrote:

have a play with


http://www.mne.psu.edu/lamancusa/Pro.../bikecalc1.htm
A sensible reply! Super! Thank!

To add to that this discussion, this "historic" site still exists in the
web archive:
http://web.archive.org/web/200306060...ish/espeed.htm

Andreas


That showed the racer doing 20.9 MPH versus 17.5 MPH for the same
effort. Again, that looks near my 25% guesstimate.

On Mon, 10 Aug 2009 08:20:54 +0100, Happi Monday strained every synapse to
present us with this masterpiece of enlightenment:

Ian Smith wrote:
Only
issue is lower and wider step gearing than typical for road, but I
haven't become fit enough to run out of gears yet. Hopefully that'll be
remedied before too long. :-)

That's interesting. My last MTB (slicks) had 21 gears with top being
42/12. That wasn't a high enough ratio for me. I now have a similar
machine with 24 gears and top is 42/11. I have fat off-road tyres on
this and I estimate it's one full gear harder to push than the old bike
(despite being a bit lighter). Now, I find top gear is fine - this might
change when I put slicks on.

Happi

On checking further, my Ridgeback has 48/38/28 front and 11-32 8-speed
rear. So top (48/11) is actually quite high; thus explaining why I don't
reach it unless hurtling down steep gradients. :-) However the rear
ratios are more widely spread than a road bike. Now that I cycle
exclusively on the road, it is rare for me to use the lowest gears.



--
My dynamic calendar at http://www.1r5.net

On Aug 8, 3:27*am, Happi Monday wrote:
Me: 26" Steel (lightweight) mountain bike with 26 x 2.1 off-road tyres
He: Specialized Aluminium-frame racing bike, "go-faster" lycra shorts,
yellow jersey, lightning helmet, cycling shoes etc.

Cutting a long story short, I burnt this guy off :-)
While relating this story to my girlfriend, I finished with "and his
bike was 25% faster than mine".
Reflecting on this later, I wondered where I pulled the 25% figure from.
I'd guess his bike was a good 25% lighter than mine, the tyres, for
sure, were thinner and slick.
Anyway, anyone have any thoughts/theories/calculations on how much
"faster" his bike actually was, compared to mine?

Also, the roads were wet, and I'm thinking this would give him even more
advantage.

Happi daze!
Monday

I'd say it's close to a 10-15% advantage based on experience and on
this power calc... http://bikecalculator.com/veloUS.html

Of course that makes the assumption you were both the same weight, had
been riding the same distance and you raced for more than 30 seconds.