I want lower gearing but have Suntour parts.

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Frankenbike
Posts: 13
Joined: 17 Jan 2018, 11:07am
Location: Totnes Devon

I want lower gearing but have Suntour parts.

Post by Frankenbike »

Hello all,
I want slightly lower gearing for my touring bike. It has a triple crankset 50 42 30 and Suntour 7 speed freewheel, the biggest sprocket is 28t. The bike has Suntour bar end shifters so I'm thinking it would be wise to go for a smaller crankset in this case. What do you think?

The bike has a Reynolds 531 ATB frame with 700c wheels and it makes my Dawes Galaxy feel light and springy by comparison!

I feel that one extra gear would make all the difference, thanks in advance for any suggestions :D
Last edited by Frankenbike on 20 Jan 2018, 4:48pm, edited 1 time in total.
Brucey
Posts: 44513
Joined: 4 Jan 2012, 6:25pm

Re: I want lower gearing but have Suntour parts.

Post by Brucey »

a new chainsset does sound like a reasonable idea. But you may be able to just fit a smaller chainring to the extant chainset to replace the 30T one, and get an extra gear that way.

cheers
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~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~
Frankenbike
Posts: 13
Joined: 17 Jan 2018, 11:07am
Location: Totnes Devon

Re: I want lower gearing but have Suntour parts.

Post by Frankenbike »

Thanks very much, how small can I go? :D
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andrew_s
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Joined: 7 Jan 2007, 9:29pm
Location: Gloucestershire

Re: I want lower gearing but have Suntour parts.

Post by andrew_s »

The existing chainset should allow inner chainrings down to 24T, but the middle is likely to be limited to 39T.

Personally, I'd go for a replacement triple (eg 46/36/24, Spa Cycles, cheaper options available). Spa also have a 4-arm chainset that goes down to 22T, but there's less choice in replacement chainrings.
You may need a new bottom bracket, and will want to move the front mech down the seat tube a bit and readjust the cable.


The other option is to just fit a cassette or freewheel* with a larger biggest sprocket. Up to 34T are available, at the cost of either larger gaps through the range, or a very big jump to bottom gear. You may need a new rear mech, and will probably need a new chain.

* Drop the wheel out, and turn the sprockets backwards. If everything you can see other than the QR/wheelnut also turns, it's a cassette. If there's an area in the centre that doesn't turn, it's a freewheel. Don't buy the wrong item.
rjb
Posts: 7199
Joined: 11 Jan 2007, 10:25am
Location: Somerset (originally 60/70's Plymouth)

Re: I want lower gearing but have Suntour parts.

Post by rjb »

The suntour bar cons were indexed for 6 speed. Are you using them in friction mode ? They were nice shifters, wish I had kept mine. :(
At the last count:- Peugeot 531 pro, Dawes Discovery Tandem, Dawes Kingpin X3, Raleigh 20 stowaway, 1965 Moulton deluxe, Falcon K2 MTB dropped bar tourer, Rudge Bi frame folder, Longstaff trike conversion on a Giant XTC 840 :D
Frankenbike
Posts: 13
Joined: 17 Jan 2018, 11:07am
Location: Totnes Devon

Re: I want lower gearing but have Suntour parts.

Post by Frankenbike »

Hi RJB,
they're Suntour pro and they are Indexed at the mo but thanks for pointing out that possibility. I like friction shifting but that would be strange on bar ends at first. I'm not sure about getting rid of the old Suntour freewheel.
My galaxy has a Suntou Perfect freewheel that is over 40 years old, i don't know what its made of but it is in near immaculate condition.
I'm in favour of a smaller inner ring right now.
rjb
Posts: 7199
Joined: 11 Jan 2007, 10:25am
Location: Somerset (originally 60/70's Plymouth)

Re: I want lower gearing but have Suntour parts.

Post by rjb »

:oops: just checked on velobase and they did do a 7 speed version. http://velobase.com/ViewComponent.aspx? ... 4&AbsPos=9
Mine were the 6 speed ones. The 7 speed version must of been the last ones before they went bankrupt. They must be worth hangjng on too, excellent build quality. :D
I can see why you need lower gears, every road out of Totnes is uphill. I remember it well, lived near Ivybridge
At the last count:- Peugeot 531 pro, Dawes Discovery Tandem, Dawes Kingpin X3, Raleigh 20 stowaway, 1965 Moulton deluxe, Falcon K2 MTB dropped bar tourer, Rudge Bi frame folder, Longstaff trike conversion on a Giant XTC 840 :D
Frankenbike
Posts: 13
Joined: 17 Jan 2018, 11:07am
Location: Totnes Devon

Re: I want lower gearing but have Suntour parts.

Post by Frankenbike »

Yeah the hills are steep!
:P
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andrew_s
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Location: Gloucestershire

Re: I want lower gearing but have Suntour parts.

Post by andrew_s »

Maeda (original) SunTour freewheels are indeed worth hanging on to - current freewheels are almost all of a lower quality, or of a weaker design even if the production quality is good.
(Forum hearsay mostly, plus a bit of local report from people still riding old tandems.)

Keeping the freewheel points towards changing the chainrings/chainset
Brucey
Posts: 44513
Joined: 4 Jan 2012, 6:25pm

Re: I want lower gearing but have Suntour parts.

Post by Brucey »

I wouldn't claim to know of all the possible variations, but some SunTour indexed levers had three modes; 6s indexed, 7s indexed, and friction, selectable via a D ring on the bezel. Neat!

cheers
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~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~
Frankenbike
Posts: 13
Joined: 17 Jan 2018, 11:07am
Location: Totnes Devon

Re: I want lower gearing but have Suntour parts.

Post by Frankenbike »

I've spooked myself reading about broken teeth on Suntour blocks only to realise that my other bike has a Suntour Freewheel too!

Can anyone recommend which size inner chainring I should go for? Its 30t at the moment.

Thanks people :D
Brucey
Posts: 44513
Joined: 4 Jan 2012, 6:25pm

Re: I want lower gearing but have Suntour parts.

Post by Brucey »

do we know what model chainset you have, exactly?

cheers
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~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~
Frankenbike
Posts: 13
Joined: 17 Jan 2018, 11:07am
Location: Totnes Devon

Re: I want lower gearing but have Suntour parts.

Post by Frankenbike »

Hello Brucey, vintage xct. 5 bolts.......I just spotted the inner chainring is 28t not 30.
Brucey
Posts: 44513
Joined: 4 Jan 2012, 6:25pm

Re: I want lower gearing but have Suntour parts.

Post by Brucey »

not familiar with XCT but is it similar to XC-pro?

Image

if so the bolt circles are 110/74 and you can fit down to 24T (derailleurs etc permitting) in the inner position.

cheers
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~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~
Frankenbike
Posts: 13
Joined: 17 Jan 2018, 11:07am
Location: Totnes Devon

Re: I want lower gearing but have Suntour parts.

Post by Frankenbike »

That's the very same one :P

I had a feeling that 4 less teeth would be about ideal so I think a 24t inner ring is the way to go.

its been good to talk this through considering the variables, Thanks!
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