Smaller 5-speed MTB cogs

Tobster86

I have an old Raleigh Triton Firejet 10-speed MTB which I commute 12.5 miles on. It must be about 20 years old; but I'm hanging on to it as all of its disadvantages will only make me fitter!

It has a 14-28 rear hub, and the largest crank gear has 48 teeth.

On downhill sections I'm limited to about 32mph because I can't physically move my feet any faster, so I want to change the gear ratios so I can go faster.

Is there such thing as a 5-speed screw-on type hub with a smaller gearset than 14-28?

Failing that, is it viable to upsize the crank gears?

armyknife

Tobster86 wrote: »

I have an old Raleigh Triton Firejet 10-speed MTB which I commute 12.5 miles on. It must be about 20 years old; but I'm hanging on to it as all of its disadvantages will only make me fitter!

It has a 14-28 rear hub, and the largest crank gear has 48 teeth.

On downhill sections I'm limited to about 32mph because I can't physically move my feet any faster, so I want to change the gear ratios so I can go faster.

Is there such thing as a 5-speed screw-on type hub with a smaller gearset than 14-28?

Failing that, is it viable to upsize the crank gears?

There used to be some shimano Megarange freewheels that had a top 13 or even 11; I've used a few as a solution to the same problem as yours. Generally they were 6-7 speed, but seemed to fit ok, and the lowest gear was so oversize and close to the spokes not point setting up the gear change to include it.

I still have a new one in the spares box, but unfortunately they're getting as rare as hen's teeth.

edit:
this was the one I used to buy, very useful for folding bikes, but no longer available:
http://www.evanscycles.com/products/shimano/hg50-multiple-freewheel-11-34t-ec016707

Norman_Castle

32 mph on a 20 year old MTB while commuting isn't fast enough for you!. How fast do you want to go?. How good are the brakes?.

Tobster86

Brakes are reasonable, roads in question are mostly NSL; the ones that aren't have better discretion applied! I'm a generally slow & high-torque pedaller and feel as though I could go faster with a couple more gears down these hills.

From what I can gather, the old screw-on type cassette hubs don't have (won't physically accommodate?) cogs with fewer than 14 teeth, regardless of number of gears; and MTB crank gears of more than 48 teeth also seem to be non-existent.

Are these reasonable assumptions, or is someone aware of an item that proves either wrong?

thescouselander

If you want to go faster maybe you should get a road bike. The bike you have wasn't intended for high speed even when it was new and I suspect finding the parts you want will be almost impossible. Alternatively you could just work on increasing your cadence which won't cost you anything.