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Thorn Crank Shorteners

Customer Reviews (10)
4.4 / 5| Write your review
£59.99
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£59.99 Please note this product has selling restrictions to your country. was
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Details
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Product Reviews (10)
Questions & Answers (3) Q & A
Details
Fits all cranks which use 8mm bolts (tapered square axles) 170mm or 175mm. Fully adjustable from 98mm to 154mm (if fitted to 170mm cranks). Manufactured from alloy (anodised) with stainless and plated fittings. This design does not damage host crank. If you have flat cranks such as TA Cyclotourist, Stonglight 49D, 99 and SR Apex then you will need replacement bolts (part # 4212). Does not fit Shimano splined or external bearing type chainsets. NB can be fitted to shorter cranks (with some difficulty) but adjustability reduced, min host crank 140mm, when fitted to this it offers a single reduced crank length of 95mm. No hardware is available for fitting to cranks down to 140 in length.
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Product Reviews (10)
Overall Product Rating 4.4 / 5
Crank Shorteners
By
20 Mar 2013
4 / 5
I recommend this product
Good simple well engineered product. Not cheap, but it will be a small volume product. Ideal when a child is too big for kiddy cranks, but too small to ride an unaltered bike.
Thorn Crank Shorteners
By
03 Nov 2012
5 / 5
I recommend this product
Quality product, easy to fit, works great. My children, 7 and 9 years old, can now fully enjoy our tandem rides.
Probably The Best Solution For People With Knee Replacement
By
03 Sep 2012
5 / 5
I recommend this product
Conscontinuously adjustable
Precise machined with a nice finish. Needed longer M8 (i recommend 12.9) bolts and some extra washers to fit the shorteners to Simano cranks with large offset. Easy to assemble and supposedly indestructible.
Half Biken Buddies
By
07 Jun 2012
0 / 5
I recommend this product
ConsWorks, cheaper,than,new,crank
ProsNot,stampled,L,R
Easy install and setup. Make 11 year old a better stoker. Some concern about Q angle but did not present a problem. Replaced pedal blocks that made it difficult to mount. Very adjustable, but limited future options on a 170 crank, Can also adjust for leg length difference.
Thorn Crank
By
29 May 2012
5 / 5
Nach einer Keiminfektion im Knie kann ich nach Prothesenwechsel
mein Knie nur noch ca 90 Grad abbiegen. Durch die Kurbelverkürzung
kann ich wieder Fahrradfahren. Danke und schöne Grüße.
New Lease Of Life - Cycling Again!
By
17 Apr 2012
5 / 5
I recommend this product
ConsAdjustable,easy fit,removeable,sellable.
ProsQuite heavy (BUT WORTH IT!)
These crank shorteners arrived so quickly & in 10 minutes I had them fitted to my Halfords Carrerra Kraken 18" MTB. I had a new right knee in January & could not peddle around fully with the ball of my foot on the peddle. Once the shortners were on & adjusted I had full circular peddling ability. I have just reyturned from a week riding in the Lakedistrict & it was fantastic. I am only 70 as well GREAT THANKS TO SJS CYCLES
Thorn Crank Shorteners
By
23 Oct 2011
5 / 5
I recommend this product
Good to get on the bike so my daughter can get stoking on the way to school! promptly delivered and easy to fit, happy days!
Thorn Crank Shorteners
By
21 Jul 2011
5 / 5
I recommend this product
Yes a beautiful quality product that enables my 6 year old daughter to be stoker on our Viking tandem.
The man in my bike shop fitted them and commented that the bolts were only just long enough. I was surprised as I thought our tandem to be standard. If I find they come loose I will buy the longer bolts.
Knee Replacement Op
By
02 Jul 2011
5 / 5
I recommend this product
Conswell made and plenty of adjustment
Prosonly able buy as a pair
got these to allow me to get back on my bike soonest. easy to fit, well made and simple instructions. i would have liked to buy one side only as opposed to the pair so will probably sell the other side on ebay (anyone interested?)
Thorn Crank Shorteners
By
14 Jun 2011
5 / 5
I recommend this product
One word, brilliant!
My 7 year old son was rapidly outgrowing the tag a long used for the school run on a daily basis. The crank shorteners mean that he can act as stoker on my tandem and grow into it as his legs get longer.
It is a quality product,beautifully machined and with everything included to fit them.
Questions & Answers (3)
Is There Adaptator To Fit Shortener On Hollow Axle ?
By
17 Sep 2015
A lot of cycle are now in hollow axle so why thorn do not develop an adaptator or crank shorteners for this kind of crank axle?
SJS Customer Service:
Hi,

It would not be physically possible to produce a crank shortener of this design that could fit to a crank with a hollow axle as there is nowhere on the drive-side of the cranks that is threaded to allow fitting too. Although cranks with hollow axles have become very popular there are still more bikes being produced with solid axle bottom brackets like squares taper bottom brackets. This style of bottom bracket is still very popular on touring bikes as well, which is what we specialize in as a shop.

Thanks.
Does The 239 Crank Shortener Fit A L/H Shimano Xt ?
By
22 Jan 2015
Are there any extra items required for this fit?

Please advise, many thanks
SJS Customer Service:
Hi,

This will not fit any modern Shimano XT crank sets as they use a hollow axle, if you have one of the really old sets with a square taper bottom bracket then this will fit without any extra parts required.

Thanks.
Will Thorn Crank Shorteners Fit On Truvative Firex
By
25 Sep 2014
Hi I need to shorten the crank length on my tandem for my son.
SJS Customer Service:
Hi,

Unfortunately not, these crank shorteners require a crankset with two crank bolts where as your cranks use Truativ's GXP system, which uses a hollow axle and a single locking bolt on the non-drive side.

Thanks.