martytardy

Another installment in my educational process: I've got an old mountain bike that I will be working on building back up after having it converted years ago to a single speed. I've still got the original triple in the front (44/32/22), but am not sure yet if I need to replace this when upgrading the drive train. Originally, the bike came with Deore LX components front and rear and an old Impel crankset. (I could find out the bottom bracket model by googling the bike model, a 1996 Diamondback Zetec.) I'm looking at going to SRAM X.7 level components front and rear and will be working on getting parts little by little over the next few months. Do I also need to upgrade or replace the bottom bracket and crankset/chainrings? Or can I leave them on and save the cost? My lbs did all my tune-ups back when I had it fully geared but there came a point that they could not tune it up anymore, telling me that the parts had essentially been worn out. (I did mostly road riding on it over the course of 8 years and estimate that I rode approximately 20K miles in that time.)

I don't anticipate doing a whole lot of heavy mountain biking, but maybe some easy single track from time to time and otherwise will mainly use the bike for riding around town and maybe commuting to/from work (adding a seatpost rack as it doesn't have braze-ons to add the normal pannier racks).

As indicated above, this is just another step in my educational process and I'm asking for sincere advice. Please don't comment on my obvious lack of knowledge on the subject. I do hope to do most of the work myself installing the parts, using as my own learning experience and will also solicit help from friends in my area that are in the know. TIA.

DOS

What parts did LBS say were worn out, the shifters/derailleurs , the chainrings /cogs, or both? I would guess at very least the latter were worn out, which would degrade shifting.

The cranks you have will work but you almost certainly need new chainrings in front and casette in back (freehub or freewheel depending on your wheel -- although maybe your replacing the wheels?). By the time you add up cost of three new rings for the crankset, you probably would be spending as much or more than you would for a whole new crankset and BB of similar or even slightly higher quality. So I'd go with new cranks

martytardy

I don't remember if they said the bb was worn out. (that was back in 2003-ish.) I do know that the cassette, shifters, and deraileurs all need to be replaced, as they were all removed when I had it converted to single speed and I did not keep the old ones, knowing that they were worn out. should I then have my lbs look at the chainrings and see if they definitely need to be replaced? If so, then I would get new cranks probably, just another part that I would need to replace. Also forgot to ask in my original post, are bottom brackets a standard size? Or do I need to watch out for compatibility with my frame?

Here's what I found for the original specs from Goodling it as well, except for the deraileurs, cassette, and shifters, I think most everything original is still on the bike:
Component GroupShimano Deore LX BrakesetTektro 870AG brakes, Dia-Compe PC-7N levers Shift LeversGrip Shift SRT-600 Front DerailleurShimano Deore LX top-swing, top-pull Rear DerailleurShimano Deore LX SGS CranksetSugino Impel 350, 22/32/42 teeth PedalsWellgo LU-946A w/clips & straps Bottom BracketShimano BB-UN52, 110 mm spindle BB Shell Width68mm English Rear Cogs8-speed, 11 - 28 teeth ChainShimano CN-HG70, 1/2 x 3/32" SeatpostLee Chi SP-211, 27.2 mm diameter SaddleTioga Multicontrol HandlebarKalloy AL002 Handlebar ExtensionsUnspecified Handlebar StemKalloy ITS-003 Headset1 1/8" threadless Dia-Compe Kontak Aheadset ST-2

DOS

Well after 20K I would think you would need new chainrings.

You need to match BB to frame and the cranks you choose. The spec you listeded give the BB specs of your current BB as"Bottom BracketShimano BB-UN52, 110 mm spindle BB Shell Width 68mm English" The last two items, shell width and threading are most reelvant to the frame , you need a BB for 68MM shell with english threading (pretty standard). The other stuff, spindle length and type, will be detrmined by the cranks you choose. Your current cranks require 110mm square taper spindle. If you go with new cranks, the type of BB you need wil change

martytardy

Ok. Thanks for the info. That's enough for this session of learning. . . I think. Will post more questions as I think of them.

LarDasse74

This is debateable, but going from Deore LX to SRAM X7 is actually a step down in terms of quality... It is unlikely that your shifters and derailleurs were 'worn out,' except maybe the jockey wheels on the rear d, which is a ~$20 fix at most... if you step into your time machine you can go back and advise yourself to change cassette, chain, cables and housing, and rear d jockey wheels and the bike will run like new.

Time machine not working either? Geez - you should take better care of your equipment ... no matter, X7 is decent stuff and replacing the crank (as others said, replacing chainrings is not usually cost effective), derailleurs, cassette, chain, shifters and cables will essentially give you a new bike. And it will be 9speed to boot!
Quality never goes out of style.

PS. Most good quality cranksets now use an integrated BB spindle (pressed into right side crank, clamped into left during assembly) and need a new BB to match... which is often, but not always, included with crank purchase.

Luckily, most monutain bike parts and frames generally have the same sizes and standards they did fourteen years ago, so you should be able to use most modern mtb parts without problem.