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Singlespeed & Fixed Gear "I still feel that variable gears are only for people over forty-five. Isn't it better to triumph by the strength of your muscles than by the artifice of a derailer? We are getting soft...As for me, give me a fixed gear!"-- Henri Desgrange (31 January 1865 - 16 August 1940)

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Old 03-26-09, 08:48 AM   #1
wintermute
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27" => 700c = Problem?

Hey,

I have a 1984 Panasonic Sport 1000 that I've been thinking about converting to a fixie. I don't have the frame geometry, but for a typical road bike, do you think I'd have a problem with pedal strike on the black top in turns if I switch out the 27" rims for 700c?
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Old 03-26-09, 08:52 AM   #2
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how long are the crank arms?
i wouldn't think the difference in wheel size would cause pedal strike...just be careful

Last edited by jpdesjar; 03-26-09 at 08:59 AM. Reason: thought it was about toe overlap initially
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Old 03-26-09, 08:55 AM   #3
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Pedal strike, not toe overlap.

It all depends on how long the crank arms are and how high the bottom bracket is. I would guess that you would be just fine though.
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Old 03-26-09, 09:00 AM   #4
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Pedal strike, not toe overlap.

It all depends on how long the crank arms are and how high the bottom bracket is. I would guess that you would be just fine though.
thanks, i realized that
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Old 03-26-09, 09:00 AM   #5
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Hm. I don't know the length on the stock arms, so I'll probably switch out for 165mm cranks. Plus I like fat tires, so I'll probably be running 38mm width. sounds like it should be okay according to you guys. thanks.
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Old 03-26-09, 09:01 AM   #6
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well 700c is only a few mm's smaller so it wont make any noticable diffrence.

your more likely to have brake reach problems. but that depends on the clearences of the frame. my 700's on a 27 frame requires long reach brakes, but the origonal U-brakes have enough drop on them to reach.

700s on a 27 frame can look a bit odd, i ended up changing to a 700 fork and using a half link to tighten the clearences up.
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Old 03-26-09, 09:04 AM   #7
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1. i wouldnt go more than 170mm on the cranks. thats from personal experience
2. stop saying fixie
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Old 03-26-09, 09:08 AM   #8
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2. stop saying fixie
Sorry, a fixed gear bicycle
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Old 03-26-09, 09:16 AM   #9
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The sport 1000's had a very relaxed geometry (for a road bike) with a long wheel base. It was an entry level,lower end Suntour equipt bike.

The conversion form 27's to 700 would drop your rim size by 8mm. Increasing the needed reach of your brakes by 4mm. Also, the tires for 27's are larger so you may see an overall drop of 14mm (this depends on many variables)
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Old 03-26-09, 09:56 AM   #10
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The switch to 700c will bring your cranks closer to the ground, and this does make pedal strike more of a problem. On many such conversions, going to 165mm cranks is a worthwhile improvement. Also consider narrower and shallower pedals.

Regarding the brake comments, a lot of older bikes came with ridiculously long reach brakes. If you already have a few mm of downward adjustment on your current brakes, you should be in good shape.
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Old 03-26-09, 09:58 AM   #11
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The sport 1000's had a very relaxed geometry (for a road bike) with a long wheel base. It was an entry level,lower end Suntour equipt bike.

The conversion form 27's to 700 would drop your rim size by 8mm. Increasing the needed reach of your brakes by 4mm. Also, the tires for 27's are larger so you may see an overall drop of 14mm (this depends on many variables)
Thanks Cynikal. So in my head, relaxed geometry = lower bottom bracket (among other things). It looks like I have enough adjustment room on the calipers to drop my brakes 4mm (have to measure). BUT, half an inch is a pretty big overall drop.

I'm just worried that in a few years it'll be impossible to find 27" tires and the wheels that I invest in will become a bunch of junk.
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Old 03-26-09, 10:16 AM   #12
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I'm just worried that in a few years it'll be impossible to find 27" tires...
Not likely, if anything I can see more tire options in the future. Its already been a quarter century since 700c started taking over.. and 27" tires still sell well. No worries mate.
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