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Replacing Rear Mech and Cassette for NC500

Posted: 27 Jul 2020, 12:03pm
by Brocky27
Hi,

I've got an old Boardman Road Sport (2013) that I've had from new. It has a 12-26t 8 Speed Rear Cassette with a Shimano 2300 Short Cage Rear Mech that won't take any cassette other than what is already on the bike.

I'm doing the North Coast 500 in a few weeks and need some bigger gears.

I'm looking at replacing the RD with a Shimano RD-R2000 Claris 8-Speed Rear Derailleur, GS. This will allow me to fit a 11-32t 8 Speed Cassette. (Should help me get up The Bealach Na Ba!)

I was going to replace the cassette with a Shimano Acera HG41 8 Speed MTB Cassette. I've got a few questions regarding compatibility.

1.) Will there be an problems with the RD swap, I think the jockey wheels are different sizes between the RD2000 and the 2300 currently fitted, although I can't imagine this being a problem?
2.) Is there any reason why I can't use the Acera Mountain Bike Cassette?

Hopefully you are able to help me here.

(Link to Bike, at the moment everything is as original https://www.thebikelist.co.uk/boardman/road-sport-2013)

Many thanks

Re: Replacing Rear Mech and Cassette for NC500

Posted: 27 Jul 2020, 12:19pm
by reohn2
You can use any 8 or 9sp long cage rear mech road or MTB which will work with 11-32t casstte you have in mind.

Re: Replacing Rear Mech and Cassette for NC500

Posted: 27 Jul 2020, 12:35pm
by mcshroom
As reohn2 says, up to 9sp, shimano rear mechs and cassettes are interchangeable between speeds and mtb/road.

Your combination should work fine. Switching to a MTB rear derailleur would give you the option of going to 34t (and possibly 36t) should you choose to.

Re: Replacing Rear Mech and Cassette for NC500

Posted: 27 Jul 2020, 1:07pm
by Brocky27
Cheers, I think I'm going to then go with a Shimano Acera M360 Rear Mech (7/8 Speed) mountain bike RD and the Shimano Acera HG41 8 Speed MTB Cassette.

Many thanks

Re: Replacing Rear Mech and Cassette for NC500

Posted: 27 Jul 2020, 1:25pm
by Jamesh
I've just brought an deore m591 which is a nice rear mech.

Will take up to 36t I think.

I ran 34 -36t on my lejog.

Cheers James

Re: Replacing Rear Mech and Cassette for NC500

Posted: 27 Jul 2020, 2:41pm
by geomannie
Brocky27 wrote:I'm doing the North Coast 500 in a few weeks and need some bigger gears.


You most certainly will :) !

The Bealach na Ba is certainly tough but by no means the steepest. I have not done the whole loop but I know from experience that there are some short 25% gradients near Drumbeg. They make one very philosophical.

Re: Replacing Rear Mech and Cassette for NC500

Posted: 27 Jul 2020, 9:03pm
by Pendodave
Very slight thread divergence....
On the shimano specs for the deore 591 (mentioned above wrt a 36t rear cog) it suggests 34t is the largest supported gear. I've seen a couple of references to shimano RDs being capable of handling a couple of extra teeth (to get to 36 in this case). Is that universally possible, or only for particular models. And if so, what part of the performance is likely to be compromised?
I'm curious because I need to get some bigger gears on my rear end, and am looking to put a long caged Sora on (I have sora bits and bobs elsewhere in the setup). The specs are that 34t is the largest gear, but I'm wondering if I could just squeeze a 36 out of it to save my old legs a little more...

Re: Replacing Rear Mech and Cassette for NC500

Posted: 27 Jul 2020, 10:10pm
by Jamesh
Brucey will be along shortly!

I did lejog on a m750 rear mech not the m591 as I implyed above.

The m750 handles 34/50 X 11-36 no problems and I expect the m591 will too.

I have one on my station/pub bike but that's running a 44/34/24 triple to 11-28 I think.


I don't think there is much difference apart from a few grams and finish.

Cheers James

Re: Replacing Rear Mech and Cassette for NC500

Posted: 27 Jul 2020, 10:58pm
by gregoryoftours
By the way, don't forget to buy a new chain as well, you'll need a longer one than what's on now, of course.

Re: Replacing Rear Mech and Cassette for NC500

Posted: 27 Jul 2020, 11:30pm
by Brocky27
Cheers all, ordered the Acera cassette and derailleur, already had an 8spd chain lying around. Should be sat down spinning up those one in fours with any luck!

Re: Replacing Rear Mech and Cassette for NC500

Posted: 28 Jul 2020, 9:04pm
by Brocky27
IMG_20200728_195530.jpg

Re: Replacing Rear Mech and Cassette for NC500

Posted: 28 Jul 2020, 10:23pm
by Jamesh
Looking good!!!

Enjoy the ride

Definitely one on my to do list!!

Cheers James

Re: Replacing Rear Mech and Cassette for NC500

Posted: 28 Jul 2020, 10:27pm
by Cyril Haearn
Bigger gears?
I think you mean smaller gears, bigger sprockets :wink:
I think the old custom of quoting gears in inches is still valid