Comparable times from MTB to road bike

[shaunharris]

Hi guys,

I'm pleased to say that after a year of training on my MTB I've finally managed to get my first road bike through the Cyclescheme at work - a Scott Speedster S40. I collected it yesterday and took it for a ride and it felt good and surprisingly comfortable, but I'm only going to get chance for a couple more rides before the Newbiggin Bay Sprint Tri on Sunday (my second sprint tri, did my first in June on the MTB).

I was wondering if any of you know of a website or a formula that'll help me roughly convert my MTB speeds into road bike speeds? Trying to work out what to aim for without blowing up before the 5k at the end.

Cheers,

Shaun

[Trisurfer]

Don't know about a formula but for me

Both over a 20 mile cycle

MTB average speed - 12-14mph

Road average speed - 20 - 22mph

[Zacnici]

Over the same course:
2006 MTB 1:04
2007 road bike 54

Calculator here:
http://www.sheldonbrown.com/gears/

Click on Gain Ratios and select say kph @ 80rpm

Enter the number of teeth on the big chainring, think yours is 50

Cassette, unlikely to have exact ratios there but all you need is to know how many teeth on the smallest cog on the rea cassette which I believe is 11

Click calculate and voila at 80 rpm with the big chainring and smallest cassette max theoretical speed 47kph, at 60 rpm 35kph

Now I say theoretical as it doesn't take into account tyres, weight, wind etc

[shaunharris]

Cheers for the info guys, I'll crunch my bike's numbers in that calculator when I get home and see what it throws up.

There's a big long relatively flat stretch of road not too far from home so I'm going to do a few trips up and down that tonight to what feels sustainable of 23k with a good 5k run afterwards.

[PC_67]

Depending on the course I'll average about 32-34kph over 40k on my road bike.

I bought a MTB recently and on a flat but uneven canal towpath I've been doing 50k, not flat out but comfortably hard, and have been averaging only 24/25kph. In fact on the flat I struggle to even get up to 32kph for even a minute. Totally different animals in my limited experience.

[shaunharris]

Well I had a go last night and I reckon I'll be aiming for about 18-19mph on Sunday. Definitely much faster than I was doing on the MTB, just wish I'd been able to get the road bike earlier and get some better practice on it.

[fire tri]

i'd have to say I used to ride an mtb all the time before starting tri's, and I had left the knobblys on and had gotten used to it and would average 17-18 but only rode it on the road, switched tires to slicks and added a couple of mph to the average, but was hard work to get that improvement.
Got a new road bike in nov last year and started training. First few times out speed seemed easy as bike was lighter and smmother rolling, then as got used to it more it all felt more natural. If you read all the blurb and forums, getting upto 18mph average is "easy" then thats the speed you start figting more against wind resistance aswell as rolling resistance etc
After 8 months of "serious" ish training i've got my average up to 20mph for a 40k ride

Sorry long winded I know

In my limited opinion/experience I would say getting upto 18mph should be relatively easy then gains over and above that take time and hard work

Ian

[shaunharris]

Thanks again for all the advice guys, thought I'd update you with how it all went.

Swim went well even though the water off the northumberland coast is a bit nippy this time of year.

According to my bike comp I averaged 19.6mph for the 23k course so well pleased with that considering it was only my third time out on third road bike!

I managed the 5.4k run at a decent pace for me as well and finished in 1:23:27 overall. A PB to try and beat next year - time to start hammering the bike miles!