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Changing/replacing a SR Suntour XCT light crankset
#1
Hi,

I am asking this one for my dad (78.5 yrs old).  He just got a bike on craigslist (Marin Redwood), comfort style.

He likes it, but wishes that it had lower crank gearing.  According to the Marin website, I see that it has a "Crankset: Suntour XCT light 48/38/28".

My dad says that he thinks the chainrings are riveted on, but his eyesight isn't the greatest, and I have not had a chance to go there and look for myself.

Do you guys know whether the chainrings are replaceable on this "XCT light" crankset?  I can't find any specific info to the "XCT light" via google.  It may be the same as just as regular XCT? 

Anyway, he would like a 22/32/42 setup. 

If the current ones are not replaceable, I see that SR Suntour XCT comes in a 22/32/42 setup.  Would that be directly replaceable, without a need to buy a different BB or anything other than buying just the 22/32/42 setup?  Also, what are the cheapest tools that I would need to tackle it myself, or would you recommend having it replaced at an LBS, and if so, what is a fair price to pay for the labor to have that done? He is living on a very tight budget so if this is a costly endeavor I'd rather tackle the project myself.

(I did not find any youtube videos where they were swapping out a Suntour crank, although I did watch the basic process with cranks made by other brands.)

Thanks.
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#2
Information 
Pretty sure a crankset like that one is rivited. If you are sticking with the same brand the spindle is probably close enough to try it out first. If not you will know which way to go with it for a replacement. For now you just need a crank puller. best crank for the money here
http://www.ebay.com/itm/SUGINO-Impel-154X-8-Speed-Crankset-24-34-42-170mm-JIS-Square-Tapered-/301501406617?pt=LH_DefaultDomain_0&hash=item4632e25d99
Sugino Impel 154X 8-Speed Crankset // 24/34/42 // 170mm // JIS Square Tapered
takes a 110/113 BB
if you pull off his and measure the spindle it may help you in your shopping.
I have suitable new Shimano Altus Fc-m311 22/32/42 and shimano un55 bottom bracket both for only $55 shipped to 48 states
There are two kinds of people in the world, "Those who help themselves to people, and those who help people!"
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#3
He is very tall, so I think he needs the 175mm crank, but I see that seller has the same one that you linked to, but with the 175mm.
www.ebay.com/itm/SUGINO-Impel-152X-8-Speed-Crankset-22-32-42-175mm-JIS-Square-Tapered-/361195704335

A couple of quick followups:
1) Does the SUGINO Impel have replaceable chainrings?

2) Does it require a new BB?  If so, which model?

3) Can you recommend a cheap/adequate crank puller that would work for the Suntour and Sugino? 
  Reply
#4
(03-08-2015, 10:31 PM)rpesq Wrote:  He is very tall, so I think he needs the 175mm crank, but I see that seller has the same one that you linked to, but with the 175mm.
www.ebay.com/itm/SUGINO-Impel-152X-8-Speed-Crankset-22-32-42-175mm-JIS-Square-Tapered-/361195704335

A couple of quick followups:
1) Does the SUGINO Impel have replaceable chainrings?

2) Does it require a new BB?  If so, which model?

3) Can you recommend a cheap/adequate crank puller that would work for the Suntour and Sugino? 

None @ this level have replaceable chain rings
you need to pull your crank to measure the spindle, I expect it to be anywhere from 113 to 118mm. The sugino would use 110/113mm

this park puller is what you want, do not buy one with integrated lever. This one will do hollow ones too for future use.
http://www.ebay.com/itm/Park-Tool-Cwp-7-Universal-Crank-Puller-Tool-/201302182649?pt=LH_DefaultDomain_0&hash=item2ede8b8af9

I use shimano un55 Bottom brackets quite a bit. Alloy cups on both sides. That is what I paired with the Shimano Fc-m311 combo I offered
There are two kinds of people in the world, "Those who help themselves to people, and those who help people!"
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#5
What year is the bike? try to post some clear close up pics of the crank and Bottom bracket area if you can
There are two kinds of people in the world, "Those who help themselves to people, and those who help people!"
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#6
he said that it is silver, so it might be a 2013 from what I saw trying to neb around on google.   I live a 1/2hr away, so I'll investigate next time I stop over there.
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#7
I have to disagree with Bob - I am pretty sure that you will find an 122.5 or 123mm long bottom bracket on the bike.  I have a 28-38-48 version in my parts bin too.

That said - if you are close and come over Saturday afternoons, I have a Shimano 22-32-42 crankset with replaceable rings off a Trek 930 that I will give you.  It has 170mm arms.  

Regarding 170 vs 175 - the shorter the crank arm, the less bending of the knees.  The generally feeling, is that no one has regretted going to shorter crank arms, but many have regretted going to longer arms.  I have one bike that I tried 175mm arm cranks on, soon it will be back to 170mm.

If you come over with the bike, I'll do the work or show you how - your choice.
Nigel
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#8
Hi Nigel,

Very nice of you to offer, but as he (and I) are from PA, I think that would be a little far!
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#9
I am now doing this crank replacement project, and the BB is 113mm. 

One of the reasons that I decided to do this project is that I just had the chain pop off during a FD downshift (from 2 to 1), and the chain jammed hard between the chainstay and granny chainring.  The chainrings (granny and middle) are so close to the chainstay that it is ludicrous -- not even a chain's width, in fact, a little more than half a chain's width.  I've never seen such little space.

Because the preference was a 22/32 setup anyway, I ordered a Shimano M311 crankset that uses 122.5 BB, and I ordered a new UN55 BB with that width, based upon the recommendation herein.

I think this will solve both issues -- preferred gearing and getting a little more space between the cogs and chainstay.

FYI - my digital scale weighing of the SR Suntour XCT 28/38/48 crankset is 1049g (2lb 5oz), so it was quite heavy.
  Reply


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