2004 Giant Rainier, won't shift to smallest chainring, BB & crank issues?
I bought a used 2004 Rainier hardtail. Has Deore LX front derailleur, seems to be stock according to:
Can't shift it to the smallest chainring!! I fiddled with the cable & High/Low screws, & the front DR tries to move WAY beyond the largest chainring for the "3" setting. The chainrings seem to be too far inboard for the front-derailleur "swing path".
I noticed the bottom-bracket sticks WAY OUT on the left side (see pic). I try to screw in the cap (on the left side, which holds the BB to the BB-shell), & it bottoms-out..showing lots of thread!
I crudely measured the BB-shell to be ~68mm. The BB (with the exposed threads) seems to be ~75mm. The color of the crank is a strange forest-green color, while the bike is blue.
Did the previous-owner try to put in a 73mm bottom bracket. In which case, the chain-rings don't go _far out_ enough, which explains the above problem?
Last edited by chimpanzee00; 05-17-2011 at 07:38 AM.
Sounds and looks like the previous owner tried to use a 73mm bottom bracket on the bike and compensated for it by using a shorter spindle length. As you noted the shell on the Rainier is 68mm. I don't recall the required spindle length though. I would suggest finding a Giant dealer near you and having them help with the BB spec. I THINK the spec for the bottom bracket on the 04 Rainier with the stock cranks was a 68X118, but I'm not positive on that. Like I said, check with a Giant dealer, they should be able to tell you.
As for the odd green coloration of the crank, that well could be fade. Anodized finishes as they age tend to fade to different colors. It's quite common for a matte black ano finish to turn green as it fades. A polished ano finish will often turn a purplish color as it fades.
Anyway, the picture definitely shows your problem, and it is as you have guessed, an incorrect bottom bracket that incorrectly positions the cranks in relation to the frame. A correctly sized bb should solve your problem.
"I do whatever my Rice Cripsies tell me to!"
Thanks for the help.
Originally Posted by Squash
This is the only info I could find on 2004 Rainier:
The bike weighs ~30 lb right now, originally a pretty nice bike (~$800 new). Judy SL front shock, nice frame, Deore LX Front/Rear derailleur, Deore LX shifters, Avid BBDB disc brakes (equivalent to BB7). Weighs 30 lbs, not bad. Except it's been neglected & has alot of surface rust: chain, front chain rings, 9-spd rear cassette. See pics. I got a good deal on this bike ($80), & I have some leeway to put in some $$..but I'd rather use what I have, wear it out, then replace.
Crankset TruVativ G-Comp, 22/32/44 teeth
Bottom Bracket Unspecified
BB Shell Width Unspecified
I don't understand what you said:
"previous owner tried to use a 73mm bottom bracket on the bike and compensated for it by using a shorter spindle length"
The Truvativ uses a Truvativ GXP BB (or any BB for that matter), so the spacing on the drive side shouldn't be "adjustable". If I get the right BB (68 x xxx), I don't see how the drive side offset would change.
However, I may have a solution.
I have a spare (almost new) Shimano FC-MC19/MC20/M440 crankset & corresponding BB (68x113). It's off of a Diamonback Topanga Comp Disc (similarly equipped hardtail to Giant Rainier: Deore LX front/rear derailleur, et al). The DB's Deore LX front derailleur is very similar, so I suspect I could swap in this crankset & be up & running.
But, am I taking a backward step with the FC-M440?? It looks & feels heavy. I bought this bike (Giant Rainier) to get _lightweight_. Given I only have $80 into it, I could spend some $$ for a nice crankset/BB.
What would you recommend?
Is the TruVativ G-Comp
The previous owner probably used whatever bb he had when the original one went out. You should be able to call any Giant dealer to get the spindle length. BB's aren't expensive.
Don't know if that crankset is that much better than your shimano. Doubt there would be a great difference.
Many people recommend the lx crankset at jensonusa. It's lighter. I'd probably just get a bb, though, since those rings look decent. Some steel wool will clean them up.
Giant website (archives) didn't specify the BB specs. I called 3 Giant Dealers, they couldn't supply the BB specs.
Originally Posted by rlouder
I use a crank puller to pull off the arms. The BB is an ISIS by Truvativ..NOT GXP!!
1 bike shop mentioned that spacers could be used to fix the problem.
I adjusted the rear derailleur as best I could, still a little buggy (wouldn't shift to the smallest cog).
I went to a couple of bike shops. 1 place solved the rear derailleur problem (i had too much tension) Called a bunch of shops, hardly anybody had the Park Tool BBT-18. Found a couple of shops, & headed over there on the bike. They sold me a Park Tool BBT-18 tool, & gave me a couple of 2.5mm spacers (!!). They guy was a MTB'er who quickly figured out what I needed: 2 2.5mm spacers on the drive-side.
Went home, yanked off the arms, discovered there was already 1 2.5mm spacer on the drive side. Put another 2.5mm spacer there, & the 2nd 2.5mm spacer on the non-drive side (which had all the exposed threads.
Put back the arms, & whoala... The front derailleur setup (Hi/Lo) setting worked with no further adjustments. Everything seems to work great.
Tentatively, the bike weighs 28 lbs (!!). For me (used to 32lb+ hardtails), this was awesome. I think I can cut down some more weight.
Thanks again for the feedback.
Ah ha! Forgot that the old Rainier used a Truvative crank set and BB. They are adjustable and useable on either 73 or 68mm shells through the use of spacers as you've found out. It's amazing how the addition of a few spacers can sort things out isn't it. As for the FMC-440 you'd likely be gaining a bit of weight if you went with that one. The old Truvativ isn't the stiffest crank out there, but they were pretty reasonable for weight. The newer external bearing LX crankset that rlouder mentions would be stiffer and maybe a bit lighter, but nothing dramatic. But it is an nice crankset. If the chain rings, and cassette are in good shape, no bent rings, chain skipping under load, etc. and the bottom bracket is good, I'd just run em till you wear em out. That little bit of rust will disappear with a new chain and bit of use. Or a little scrubbing with a stiff bristle brush and so degreaser will take it off as well. But if you really wanted to get a new crankset, the LX from Jenson is hard to beat.
Originally Posted by chimpanzee00
As for what I was driving at earlier. Some misinformed people think you can get away with using a 73mm bb in a 68mm shell by using a shorter spindle length. All this does is move your chainline on the drive side inboard and places your non drive side crank arm pretty close to the stock postion, the non drive cup won't thread all the way in, and it screws up your front shifting just as you described. But as soon as you said Truvative ISIS the light bulb lit up!, DUH!!! I'd forgotten that the 04 Rainier used the Truvative system and was adjustable for use with either 68 or 73mm bb shells. Anyway, the way you describe the way the previous owner had that Truvative bb set up, one spacer on the drive side and nothing else, it would exactly mimick the symptoms of a 73mm bb with a shorter than recommended spindle. I work in a shop and you wouldn't believe the cobbled up messes I've seen when it comes to bbs and cranks that people try to get to work. The 73 in a 68 with a shorter spindle is common. Folks just seem to forget that the bb body and spindle are symeterical.
Gladd you got it sorted out.
"I do whatever my Rice Cripsies tell me to!"