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Shimano Nexus SG-8R31 8-Speed Rear Hub w/o Fittings - 36 Hole - SHOP SOILED

£89.99 Please note this product has selling restrictions to your country. was
Manufacturer : 
SJS Cycles part number : 
Manufacturer part number : 
PLEASE NOTE: This hub will not work with standard Shimano 3-notch sprockets; fits 18 spline sprockets.

Cheaper than buying a new internal!
8 Speed, Silent Clutch,Shifting Power Modulator, Standard Driving Efficiency, Use Shifting Lever SB/SL/ST-8S20 (SL-S500).
Roller Brake Compatible, Shell Material: aluminum, Shell Finish: painted (slight marks)
Gear Ratio Total Difference: 3.07.
Gear Ratio 1: 0.527.
Gear Ratio 2: 0.644.
Gear Ratio 3: 0.748.
Gear Ratio 4: 0.851.
Gear Ratio 5: 1.0.
Gear Ratio 6: 1.223.
Gear Ratio 7: 1.419.
Gear Ratio 8: 1.615.
Axle Length: 184mm.
Over Locknut: 132mm.
Accepts Spokes 13g or 14g
Chain Line: 42.7mm.
Cassette Joint: CJ-8S20, CJ-8S40.
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Questions & Answers (6) Q & A
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Questions & Answers (6)
Brompton Titanium Frame
10 Mar 2021
I understand that Brompton rear triangle needs to be stretched to accommodate this hub.
Would this be a bad idea for a Ti rear triangle?
We do not recommend this for steel or ti, you would need to talk to a frame builder.

Is compatible with 37sj9801 internals?
10 Feb 2021
Hi, I need the internals for an sg8r31 hub it's to fit a belt drive and roller hub. I understand I need a 37j9801 is this compatible? I would only be using internals. Thanks
Thank you for your enquiry, sorry this is not suitable due to internal differences and we have been unable to obtain technical information from Shimano so unable to confirm further.
WD 11/02/2021
Compatibility SG-8R31
14 Dec 2020
I need to replace my SHIMANO NEXUS SG-8R31 and I would like to know if any of the electronic models (DI2) are compatible with this internal hub.
Thank you
You cannot use this hub with DI2 parts.

JK 14.12.20
To replace SG-8R31
12 Jul 2020
Need one to replace my SG-8R31 on mt trex bike belt driven is this the one Thank you Had bike for about 6 years no trouble even taken it to NZ and back or could it be replaced with the RG-8R36
We cannot confirm compatibility as it seems the SG-8R36 is a discontinued item.
What is a standard 3 notch sprocket?
26 May 2020
My Kalkhoff EBike has one of these hubs and is making very loud "clicks" when the wheel is rotated forward. It sounds like a broken ball bearing or broken paul but I haven't dismantled the hub (yet).
Can you give me any advice on the likely cause of this problem and do you supply spare parts to component level?
My current hub is black, and I would prefer to change the internal parts rather than the whole hub - can I use the parts from the hub you have for sale in this way or is there some other compatibility check that I need to do first (date of manufacture, serial number for instance)
Many thanks
Hi, a Shimano 20T Sprocket for Nexus Geared Hubs - Y32203620 our part 23008 is an example of a standard 3 notch sprocket. These are normally used on chain driven drive trains. This hub will not accept this type of sprocket, it looks like it was built for drive belt type sprockets like the Gates belt system but we can't be sure which one. There are next to no tech docs on this setup.

Unfortunately with out seeing and possibly stripping the hub down it is hard to say what may be wrong, it would be worth contacting Kalkhoff as they might have experience of the same problem.

The internal parts are generally interchangeable, Shimano don't date or serial number these hubs.

Can internals of this be used to repair existing SG8R31 fitted within 32 spoke hub ?
19 May 2020
Hi, yes. You will not be using the hub shell. Thanks