Eeeking a little more speed out of a tongsheng, will a road bike help?

[neilhapgood]

Hi all,

so I have a TSDZ2 on a mountain bike, 750w, and its all good, love it. I converted the bike so I could put some equipment in a trailer and cycle 7 miles to the beach to go kitesurfing.

However I have just got another job which is 8 miles away, mainly flat and I want to cycle the commute. My current set up will cruise along happily at 20mph, however it would be great to get that up to 25mph for the daily commute.

I want to stick with the TSDZ2, currently I am at max RPM to get 20mph therefore I am wondering if a road bike would be faster at the same RPM as it has bigger wheels, I saw this table on endless sphere:


My maths is poor but I think according to this table, for the same RPM, I would only get about 5% more speed having 700c wheels instead of 26inch, is that right?!

Therefore my questions are:

1 - is my maths right or would bigger wheels make more of a difference then 5%?
2 - would changing the front cog from a 42t to a 44t give me 5 more MPH?
3 - would a road bike being any other advantages to speed if at mak rpm?
4 - any other tips or should I just leave 5 mins earlier and stop worrying about it?!

 

[joelectric]

Bicycle Gear Speed Cadence Table | BikeCalc

Calculate cycling speeds at a specified cadence given chainring, sprocket, tire and wheel sizes.

www.bikecalc.com

 

[vfr400]

Yes, about 5% more dpeed for the same crank rpm is about right.

A road bike has a lot less resistance at 20 mph than an MTB, so you'll use less battery and you'll be able to maintain your top speed more easily.

You'll need to go up to at least 48T, which would give 24 mph.

 

[Gavin]

If you like every other aspect of your MTB then an alternative to two bikes would be two wheelsets.

Set 1- fat rims/ knobblies/ lower-geared cassette for off-road.
Set 2- thinner rims/ road tyres/ raised gearing for road work.

Less clutter in the garage and it gives you a spare set of wheels if you ever get a puncture/ broken spoke and need a quick turnaround...