Need lower gearing
 

I have on older Trek 830. The crank is 48/38/28 with a 12-28 cassette. I need a lower end. What is the easiest way to get there without trashing everything. Can I install a smaller crank? Any ideas please as I am a newby at this.

The easiest thing to do is to replace the front 28 with a 24. To do this requires removing the cranks - if you don't know how or have the proper tools, get a mechanic to do it. If you want a dramatically lower gear, replace the cassette with an 11-32 and the rear derailleur with a long cage mountain bike derailleur (necessary to take up slack with the greater range of gearing) such as a Shimano Deore, LX, XT. Doing both will give you a super low gear without losing your highest gear.

To get the best answer you're going to need to offer more information. Is the rear cog set a freewheel or a cassette? How many cogs? If you can put a 26 small ring on the front that may be the best option. Sometimes the best place to look for older bike parts is at your local bike shop.

Al

A smaller granny only works if the rings are removable separately,which isn't often the case on lower end mtb. Bigger rear cog cassettes and freewheels are available.The present RD might handle a 32 cog.

You can replace either/or the cassette + rear derailleur or the crank set with ATB components. That allows you to get up to a 32 big cog on the rear. You may exceed the ATB long-cage derailleur official capacity, but it's of little consequence as it only causes chain rub when the small ring and the two small cogs are used. You shouldn't use those chain angles anyhow. If you inadvertently shift there, the noise will alert you and there's no damage to be done anyhow. Just don't get the chain too short.

The ATB crank will give you 22/34/44.

I've mixed and matched road and ATB components for years (decades?) to get the gearing I like. I've also gone to full ATB drive train on a touring bike. My wife uses that now. It all works well and easy to do if you have sufficient knowledge or have a bike shop that does. If you do it yourself, you can tinker and see what works best for you. It's also a great learning experience. There are plenty of books out there plus the web for info.

My present bike uses a cyclocross frame with a French TA crank set (big $'s), an XT long-cage rear derailleur with an Ultagra front. The gearing is 22/36/46 with a 12 to 28 ultegra cassette. I have used a 12 to 32 XT cassette by adding a few links of chain. I keep that as a kit for the mountains as I live where there are only rolling hills and I don't like to grind. I like to spin.

Al

The 830 is a mtb.

How much easier of a hill climb gear do you think that you need? How much are you willing to pay for it?

Your lowest hill climb gear today is 27 gear inches.
Replacing your cassette for one with a 32 tooth cog will give you a 24 gear inch low.
Replacing your 28 tooth granny with a 24 tooth ring will give you a 23 gear inch low.
Either is essentially the same as having one more gear to downshift into than you have now.

If you think that you need a lower hill climb gear than that, you are going to have to replace multiple parts and the cost just keeps going up.

I wondered about that. I didn't know mountain bikes came with that high a ring set, so I convinced myself it had to be a road bike. Oh well---------

Al

Common fare in the old days.

Thanks to all. I think going to a 24 chain ring is the only reasonable solution. That would get me from a 1.0 to a 0.85 ratio and help a bunch. Other than that I will sell the bike and get a new one. I think most of the new Treks are .80-.69 ratios in Granny gear.