# Calling all bicycle gurus.
**URL:** https://boards.straightdope.com/t/calling-all-bicycle-gurus/114330
**Category:** Factual Questions
**Created:** [June 16, 2002, 7:03am UTC](https://boards.straightdope.com/t/calling-all-bicycle-gurus/114330 "2002-06-16T07:03:41Z")
**Posts on this page:** 7
**Page:** 1
### Author:  [@Poloin99](https://boards.straightdope.com/u/Poloin99)
#### Post date: [June 16, 2002, 7:03am UTC](https://boards.straightdope.com/t/calling-all-bicycle-gurus/114330/1 "2002-06-16T07:03:41Z")
I have a seven speed drive train and need a new rear derailer. The question is can I buy an XTR mega nine and make it work on my seven by locking it out using the adjustment screws?
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### Author:  [@casdave](https://boards.straightdope.com/u/casdave)
#### Post date: [June 16, 2002, 10:43am UTC](https://boards.straightdope.com/t/calling-all-bicycle-gurus/114330/2 "2002-06-16T10:43:01Z")
I think you need to go to a good local cycle shop.
In this case though I think you’d be ok, if you attempt this then I would lock out the largest and smallest sprockets, partly cause you hardly use them anyway, also it will allow the chain to run straighter.
I do think that unless you plan to go to nine in the future that you are spending an awful lot of wonga unnecassarily, it would cost significantly less to put another seven speed derailler on.
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### Author:  [@Poloin99](https://boards.straightdope.com/u/Poloin99)
#### Post date: [June 16, 2002, 1:00pm UTC](https://boards.straightdope.com/t/calling-all-bicycle-gurus/114330/3 "2002-06-16T13:00:31Z")
Got any idea where I can get an XTR 7-speed derailler? I agree with you 100%.
As for a good bike shop they said it would work but they had never done it. Furthermore they charge an XTR price for XT products.
The reason I am skeptical is the width of the 9-speed chain vs. the 7-speed.
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### Author:  [@waterj2](https://boards.straightdope.com/u/waterj2)
#### Post date: [June 16, 2002, 2:54pm UTC](https://boards.straightdope.com/t/calling-all-bicycle-gurus/114330/4 "2002-06-16T14:54:45Z")
You could always try Ebay. I’ve had pretty good luck finding bicycle parts there.
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### Author:  [@casdave](https://boards.straightdope.com/u/casdave)
#### Post date: [June 16, 2002, 5:20pm UTC](https://boards.straightdope.com/t/calling-all-bicycle-gurus/114330/5 "2002-06-16T17:20:59Z")
Yup, auction sites are a great idea, and especially for stuff like this.
There are those who specialise in obtaining things that have been superceded by the latest big thing and they put them out for much better money.
Does it have to be Shimano XTR ?
Just about everyone else makes their stuff compatible to Shimano, some of it even better quality.
As for the chain width, if you put on a 9 speed chain you should be ok it you run a 9 speed block.
If you go this route I guaruntee that you will end up making it all nine speed 'cause its just human nature. This will cost you lots.
The gains to be made on 9-speed are minimal due to chain crossovers and gear duplication, and from what I’ve heard, the 9-speed sprockets don’t stand up too well to being plastered in mud which makes a most effective grinding paste.
I’ve found that with Shimano it is best to wait a year or so and let others make copies, this always prompts Shimano to put out better value stuff with the same specification, sometimes its virtually the same as the previous best thay did.
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### Author:  [@Shiva](https://boards.straightdope.com/u/Shiva)
#### Post date: [June 16, 2002, 5:21pm UTC](https://boards.straightdope.com/t/calling-all-bicycle-gurus/114330/6 "2002-06-16T17:21:21Z")
Sheldon Brown says [“yes, you can”](http://www.sheldonbrown.com/harris/derailers.html#rear).
> [@](#):
>
> Rear derailers often are referred to as “7-speed”, “8-speed” or “9-speed.” This is not as important a distinction as it might appear. Current model derailers are pretty much interchangeable within brands. A “7-speed” or “8-speed” designation generall just indicates that the derailer is an older design, or a cheaper model. They’ll all work with all 3 systems, though the models marked “9-speed” will generally be slightly better (whatever cluster you use.)
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### Author:  [@Poloin99](https://boards.straightdope.com/u/Poloin99)
#### Post date: [June 16, 2002, 5:33pm UTC](https://boards.straightdope.com/t/calling-all-bicycle-gurus/114330/7 "2002-06-16T17:33:20Z")
Thanks guys you have been a big help. I bought an XTR for $71 including shipping. The site said it was compatible with 7/8/9 speed bikes.
On the human nature of 9-speed… Seems like too many gears to me. All my buds have the mega nine. They would prob diss me about my antiquated 7-speed if the could catch me. 😃