Bicycle Mechanics - 42 >> 52

This might sound completely ridiculous.I have a Schwinn Mesa GSX mountain bike with a 42 teeth crank set. I was wondering if it would be physicaly possible to change it to a 52 ?? I am well aware that i would have to change a lot of stuff on the bike but i'm willing !!


thank you !!

This might sound completely ridiculous.I have a Schwinn Mesa GSX mountain bike with a 42 teeth crank set. I was wondering if it would be physicaly possible to change it to a 52 ?? I am well aware that i would have to change a lot of stuff on the bike but i'm willing !!


thank you !!I'd really be surprised if you could chances are you'll hitt the chain stay with the increased diameter of the 52 ring. Why would you want such a large gear on a mountain bike when it would honestly be cheaper to just buy a used Road bike?

i was thinking Hybrid Performance ,because i use it for asphalt only .

This might sound completely ridiculous.I have a Schwinn Mesa GSX mountain bike with a 42 teeth crank set. I was wondering if it would be physicaly possible to change it to a 52 ?? I am well aware that i would have to change a lot of stuff on the bike but i'm willing !!


thank you !!

Depends. Projects like this can be a lot of fun if you have a big box of spare components. If you don't it probably won't make economic sense.

You can almost never change just one part on a bike. Everything on a bike works in concert so when you change one part, you frequently have to change something else in order to make it all work. This kind of conversion usually requires trial fitting. Believe it or not, sometimes the deal breaker turns out to be the cable stop location.

You have to start by selecting a crank. Crank specs will recommend a BB spindle length. Spindle length will frequently be listed something like 113/118. That's to get a straight chainline. In this case, use a 113mm spindle on a bike with 130mm dropouts and a 118 spindle on a bike with 135mm dropouts. If that gives you interference with the chainstay, you'll have to fudge.

The next issue is the front derailleur. The arc of the derailleur has to match the arc of the big chainring fairly closely. The one that you have now probably won't work. When you try to move your derailleur up on the seat tube so that it will clear the big chainring, you may find that the water bottle mount is right where you want the derailleur to go. Also, if you fudged on BB spindle length, you might find your derailleur of choice doesn't have quite enough swing to engage your big chainring without rubbing.

All of the derailleurs that I'm aware of that are designed to handle a 52 tooth chainring are downpull. Most mountain bikes have cable stops that are designed for uppull derailleurs. One solution is to install a clamp-on pulley on the bottom of your seat tube. You'll have trouble making that work if your seat tube is flared at the bottom or if space is limited.

Good luck.

Depends. Projects like this can be a lot of fun if you have a big box of spare components. If you don't it probably won't make economic sense.

You can almost never change just one part on a bike. Everything on a bike works in concert so when you change one part, you frequently have to change something else in order to make it all work. This kind of conversion usually requires trial fitting. Believe it or not, sometimes the deal breaker turns out to be the cable stop location.

You have to start by selecting a crank. Crank specs will recommend a BB spindle length. Spindle length will frequently be listed something like 113/118. That's to get a straight chainline. In this case, use a 113mm spindle on a bike with 130mm dropouts and a 118 spindle on a bike with 135mm dropouts. If that gives you interference with the chainstay, you'll have to fudge.

The next issue is the front derailleur. The arc of the derailleur has to match the arc of the big chainring fairly closely. The one that you have now probably won't work. When you try to move your derailleur up on the seat tube so that it will clear the big chainring, you may find that the water bottle mount is right where you want the derailleur to go. Also, if you fudged on BB spindle length, you might find your derailleur of choice doesn't have quite enough swing to engage your big chainring without rubbing.

All of the derailleurs that I'm aware of that are designed to handle a 52 tooth chainring are downpull. Most mountain bikes have cable stops that are designed for uppull derailleurs. One solution is to install a clamp-on pulley on the bottom of your seat tube. You'll have trouble making that work if your seat tube is flared at the bottom or if space is limited.

Good luck.Mr. Grouch you made your case so much more eloquently than I would have. :D

Smaller cassette?

Smaller cassette?


Would you be able to do that without changing anything else? Except maybe taking out a few links in the chain if its too long. I find I ride mostly on the road at the moment and even offroad the smallest gears rarley get used.

if you ask me, it's very likely that you'll be able to just switch your front chainring and crankarm, and move/readjust your derailleur, and everything will be fine and dandy.

The only other issues I think are likely are that you will need more chain and that it'll take a while to get your derailleur to be in the right spot and have its set screws adjusted right.