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Old 09-08-10, 06:07 PM   #1
alangeering
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Accident damage - how much to replace? GT Strike with RX-100

I'd like some advice on what parts I will need to change to get my bike back on the road.

Bike is a GT Strike circa 1997/1998 with all RX-100 equipment

Beyond repair:
Rear Derailure
Hangar bit (bit that holds derailure snapped)
Chain

Damaged:
Both wheels buckled
Everything else just scuffed

Good:
Frame seems unaffected
Brakes still work fine
Crank/pedals/front derailure OK


I'd like to get it back on the road only replacing the bits I need to.

Is there a current generation drop-in replacement for the RX-100 rear derailure?
If I go for Shimano 105 derailure do I need to replace my RX-100 shifter and cassette as well?

I'm an aircraft mechanic so can do the work myself, I'm just clueless on the different Shimano choices and which would be compatible with my current set-up.

Thanks in advance,
Alan G
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Old 09-08-10, 08:44 PM   #2
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Quote:
Originally Posted by alangeering View Post
I'd like some advice on what parts I will need to change to get my bike back on the road.

Bike is a GT Strike circa 1997/1998 with all RX-100 equipment
I'm guessing this is your bike:
http://www.bikepedia.com/quickbike/B...rike&Type=bike

Not knowing much about it, it sounds like the shifters should be compatible with a new 8-speed Shimano derailleur. And that the derailleur should be compatible with your current 8-speed cassette. Though you you can get a new 8-speed cassette for $30.

Sounds like the wheels will need to be rebuilt with new rims and spokes (you basically need new wheels). But it depends... How bad are the wheels? Are the rims bent, or are the wheels just wobbly?
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Old 09-09-10, 02:25 AM   #3
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Originally Posted by bijan View Post
...a new 8-speed Shimano derailleur. And that the derailleur should be compatible with your current 8-speed cassette. Though you you can get a new 8-speed cassette for $30.
In theory derailers could be made with narrower cages as the speeds go up, but I've never had any trouble mixing supposedly 7-8-9 speed derailers with whatever chains and cassettes.
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Old 09-09-10, 08:08 AM   #4
alangeering
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Originally Posted by bijan View Post
Yep, that looks like it, it's currently at my parents house in pieces so I can't compare all the details. I did think that the shifters were labled RX-100 instead of 105 but I'm not sure.

Basically I want to get all the bits together so I can rebuild it when I next visit my parents and bring the bike home.

Thanks for the advice. I will have a look for new wheels. I think the hubs are OK but nothing else is.
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Old 09-09-10, 08:45 AM   #5
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Before you go sourcing a derailleur, make sure you can get a suitable hanger. The linked specs say it's replaceable.
If you can, pretty well any current Shimano derailleur will work, you'll need a mid-length or long cage to work with your triple, you want hanger mount, not the integrated claw type. If you're looking to save some cost, look at "Mountain" parts, they tend to be cheaper in the lower end of the range.
If you can't find a suitable hanger, you'll need to use a derailleur with the integrated claw that mounts to the axle.
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Old 09-09-10, 09:18 AM   #6
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Sadly the 8 speed shifters currently available from Shimano are not nearly as nice as the RX-100. The Sora and 2200 models have a downshift mechanism with a little 'mouse ear' button on the inside, and its placement makes it very difficult to downshift when your hands are on the drops.

Luckily, since you are replacing rear derailleur and shifters and cassette anyway, you can just get 9 speed compatible parts (all derailleurs from $35 and up are 9 speed already).

If I were you, I would get Tiagra STI levers (same quality as RX-100, but more reliable), a Deore derailleur (same quality as RX100 but with a wider gear range), a 9 speed cassette, and a 9 speed chain.

If your existing hub is still smooth then it might make sense to rebuild or have it rebuilt with a new rim and new spokes... otherwise just get a whole new wheel and make sure it is properly hand tensioned by a good builder. A 9 speed cassette will fit onto the same hub as an 8 speed cassette.

You crank and front derailleur should work fine with 9 speed chain.

This is all assuming you can get a new derailleur hanger.

Edit:

Beofre you buy anything, add up the prices of the parts you have sourced... you can get a new similar quality bike for ~$800
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Old 09-09-10, 09:51 AM   #7
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If it was some sort of impact or the bike got driven over or jammed into a wall to cause all this damage then I'd suggest you set up some jigs to actually measure the frame for straightness before you forge ahead with replacing those parts. Other bikes that have been written up here desribing similar or less damage to the wheels and other hardware turned out to be tweaked well enough that it made riding them a bit off. To the naked eye they looked OK but once measured more carefully the frame was found to be bent slightly. So before you leap onto buying parts I'd suggest coming up with some tricks to level and test the frame for correct alignment to be sure.

There's a purely financial aspect as well. By the time you add up the list of parts you'll need I'm going to suggest that you can buy a newer and upgraded used bike off your local Craigslist or similar for the same amount. A bike that was not jammed or crashed or driven over. You're already up to wheels, likely a cassete given the damage to the derrailleur area, a hanger and possibly new brifters to make it all work.
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Old 09-13-10, 12:27 PM   #8
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Thank you

Thanks guys, very helpful advice.

I've been able to get a replacement hangar so that's not a problem any more.

The accident was not big on "impact" - I had to avoid a car and went into deep balast/gravel. I was only doing around 20 mph. I managed to ride the bike for 1 km (one gear only) before the rear mech jammed, exploded across the road and threw me off into a post (this is where the wheels got bent).

I'm going to see what can be done with the wheels.

Is there anything different between the chain for 8 speed and 9 speed?
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Old 09-13-10, 04:54 PM   #9
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9 speed chain is narrower over the outside to fit between the closer spaced rear cogs. They are usually a bit more money.
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