Ambitious but Rubbish - How to improve on the road?

chainsucked

After procrastinating about about 2 years on a bike build I finally got my act together and have my dream bike.

As I do not have the space to store more than 1 bike, I just have the 1 with 2 wheelsets.

1 nice chunky wheelset for more mountain-ey terrain and the other a super lightweight XC wheelset with some 1.5 road-ey kevlar reinforced tyres.

Normally this would be enough of a compromise but to add to the complications, I decided to go single chainring. The current 32t chainring is amazing for climbing but not nearly big enough for the downs or even flats (36t was my original thought but I am now considering 40t).

I always built this to be a mountain bike "bodged" to also work on the road, I would not want to compromise it. I was just wondering what the easiest way of getting it to ride a little faster on the flats and the downs would be.

I've specced everything to be fully interchangeable, any changes to the cassette would have to be reflected in both wheelsets.

I know full well that it will never ride as well as a road bike, it was not designed for that but I can't help but think that there is more that I can do. I have been training pretty hard and would be willing to train harder if necessary to get my legs up and running with a bigger chainring on hilly terrain.

I'm sure this setup has more potential, I just don't have the experience to know where to go with it. I've seen a few posts in here with people using their hardtails are commuter bikes so I'm sure I could learn a thing or two from them. I did 60 miles yesterday and felt pretty good, I just want to be able to do it faster at a reasonable cadence! Are there any super thin, super slick tyres that would fit a mountain bike rim?

Are any of your Bikeradar gurus able to help this idiot?

supersonic

Put a double chainsaw on!

cooldad

Tyres aren't going to increase your cadence.

Ferrals

chainsucked wrote:

I just want to be able to do it faster at a reasonable cadence!

Get fitter?? I did read about cranks designed so you could change the front ring without removing the cranks, might be the answer if you want single ring, just switch front rings depending on application? No idea what cranks they were though.

tootsie323

How to improve on the road?

Cover it in grass and small rocks, perhaps a few roots, add some gradient - hey, presto...

paul.skibum

The difference in riding off and on road even with knobbly tyres means that a single chainring is rarely going to work. A climb that you can clean on a 32T chain ring and 11-36 probably wont be cleaned ona 40T chainring so by dropping a larger chainring on the front you will be inhibiting the bikes performance as a off road machine in exchange for the benefits it gives you on road.

Fit a double chain ring or buy another bike for one road. Or hold the brakes slightly on road to make it harder!

Initialised

Maybe a 36 x 10-42 cassette: http://www.chainreactioncycles.com/sram ... -prod91007

A double would possibly be cheaper and gives you far more options.

Check the numbers here: http://www.bikecalc.com/speed_at_cadence

A 26" bike can usually fit 700c (29") wheels with skinny tyres meaning conventional road rubber like 25mm.

ilovedirt

Double chainring sounds like the best way - you're gonna struggle on most mtb climbs with a 40t ring!

The Rookie

The trouble is the 1.5" tyres are a smaller rolling radius than the MTB tyres taking your gearing the wrong way, so you either need wider (larger radius) slicks or use 29er wheels with road tyres.

My commuter is a 1x9 on 26x1.5" tyres, I use a 46t chainring and an 11-28 cassette as that gives the right range of gears for where I use the bike (mostly on the one fixed route to work!) I could have a wider range cassette of course, fastest I have gps logged is 45.5mph not many hills in May area though so I can get away with that gearing.

Northwind

supersonic wrote:

Put a double chainsaw on!

That's your solution for everything!



Road just needs a big ring, there is IMO no single ring that can work offroad and on. Trouble is, road use with 26 inch wheels needs a big chainring, which is a problem offroad, you'll struggle to even buy one that'll fit a 4-bolt chainset and it'll cost you tons of ground clearance too.

My advice? Get a road bike if you want to go on the road. You can get something functional for buttons, road bikes are very simple machines compared to mtbs. Or a hybrid, I can't get on with drops. But it's not possible to make one bike that'll be good for both jobs and you'll spend more trying than you will just nipping down to decathlon and buying a Triban 3, or going on gumtree and buying something terminally uncool.

chainsucked

Many thanks for all of your responses everyone, I have quite a lot to think about!

Unfortunately I don't have the space for 2 bikes so it was always going to go one way (not that I have anything against road bikes!).

That Road Calc is very enlightening, I was almost in hysterics picturing my legs doing 130rpm to reach the ludicrous speed of 28.14 miles an hour.

For some reason I had the idea lodged in my head that the tyres were going to make all of the difference but this is clearly a gearing issue. Double chainring is by far the most practical solution but I can't help but wonder if I could get away with a 40t.

The front mech on my previous steed gave up the ghost so I ended up only using the biggest ring for months on end. It was an 8 speed deore triple setup which would have resulted in me using a 44+ chainring with a 10-28 cassette. I guess I have lots of experience making life difficult for myself

Maro

My old hardtail has a 38t ring on the front, with 11-32 cassette it does ok but not perfect on road and occasionally spins out on steep offroad climbs. However, I'm in agreement with the general population, for the best solution fit 2 rings.

bob6397

My mtb has a double on the front - a 27/42 (36-12 10 speed cassette)and this is about right for me around the hills here (max speed about 35 before spinning out), but you'll never get the same kind of speed from even a 40t on the road - the climbing ring on my "compact" roadie is 36 (not low enough with the 12-26 9 speed cassette) and the big ring a 50 - not high enough as i start spinning out at 45-50mph with that combination.

therefore, in my opnion, fit a double on the front as even with doubles on both mine i stuggle for top speed, but i happily sacrifice some of this on my mtb for lower climbing gears. but it does depend on your current cassette - make sure you have a good wide range on here and that will let you have a greater difference between the front chainrings - have a mtb one and a road one.

bob6397