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 Post subject: STRANGELOVE
PostPosted: Fri Aug 26, 2011 12:37 pm 
MacRetro rider
MacRetro rider

Joined: Fri Feb 09, 2007 4:16 pm
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As Dr S suggested a thread just about frame building I thought i'd start one as I've got questions.

Si, have you heard of offset rear triangle and if so do you reckon you could build one.
I heard of this years ago and thought now thats clever. You build an undished rear wheel and offset the rear triangle toward the drive side, Result very strong rear wheel that can still do deralier gears. its an idea I quite fancy and used to be done by Orbit Cycles for their tourers.
There may be issues with this mind so opinions sought :wink:


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PostPosted: Fri Aug 26, 2011 12:55 pm 
MacRetro rider
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I'm pretty sure a few of companies do that velo - seen some downhill bikes with it.


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PostPosted: Fri Aug 26, 2011 1:41 pm 
retrobike rider / Gold Trader
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The Pace RC100 had that back end. Personally I'm not convinced. Yes its fine in theory but how many rear wheels have collapsed on you in all your years of cycling? More important for me is chainline. Dishing out the wheel further means you have to consider Q factors to get a good chainline etc. Mountain bikes in my view, have always been hampered by a lack of tyre clearance when using a big tyre- something that is desirable on a hardtail to give comfort.. Adding an offset rear end to that tyre clearance requirement means you need wider cranks (which the RC100 had) and end up with heals clipping stays, which means more work in bending stays in and out to get them out of the way. It all adds complication chasing a problem that isn't really a problem to start with.

The frame i'm finishing at the moment has clearance for 2.5 tyres and the stays still needed crimping beside the wheel path despite them having a pronounced S bend for heal and crank movement. Even now the chainstay length dictates that anything bigger than a 38T chainring won't fit without having a crank with a large offset, which in turn would bugger up the chainline.


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PostPosted: Fri Aug 26, 2011 5:16 pm 
MacRetro rider
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Thanks Si, always good to hear the expert view, I can now knock that idea on the head :lol:

Will all your bikes be mtb's, I dont actually need another mtb, I'm thinking a relaxed geometry rugged tourer but with disc brakes is more me. An all rounder for less extreme offroad stuff.

Whats your view on suspension. Is it really needed or can relaxed geometry such as the old clunkers allied to complient tubes make a big enough difference. How complient are modern tubesets ?


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 Post subject:
PostPosted: Sat Aug 27, 2011 12:07 am 
Gold Trader / MacRetro rider
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Mono blade.Like the one Mike Burrows designed for Adam hart Davis :?
It was mono stay too i think :?


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 Post subject:
PostPosted: Tue Aug 30, 2011 9:37 am 
retrobike rider / Gold Trader
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velomaniac wrote:
Thanks Si, always good to hear the expert view, I can now knock that idea on the head :lol:

Will all your bikes be mtb's, I dont actually need another mtb, I'm thinking a relaxed geometry rugged tourer but with disc brakes is more me. An all rounder for less extreme offroad stuff.

Whats your view on suspension. Is it really needed or can relaxed geometry such as the old clunkers allied to complient tubes make a big enough difference. How complient are modern tubesets ?


Ha, don't know about being an expert! It's very early days and I'm having to learn a new craft. Ask me again in 20 years and I might have a better idea.

Suspension forks? I think its a good idea to be flexible. Building around a fork is all important- you can then choose suspension or a corrected length rigid fork on the same bike depending on where you are going. The Cotic Soul is a great example of this kind of thinking. Its great with a 100mm fork for general trail use, awesome with a 140mm for big stuff but still compliant with a rigid fork for less challenging stuff. That said I rode rigid over the Blue Man on Saturday which is the toughest trail I have ridden in 25 years.
It is difficult to make a bike as good as that, but with good design and careful tube selection you can have a bike that is a true jack of all trades.

Interesting thought on your ideal bike. I've been working on a design this weekend for a bike that would fit that description. I want to build a bike that does everything from fast xc singletrack to touring. Something like the Jack Taylor roughstuff bikes. Its a flat bar cyclocross bike with attitude really. Comfortable and compliant and built to handle rough trails and the added weight of camping/touring gear. More upright than a cross bike too with and easy going riding position. It will run 650b wheels and have clearence for a 1.9 tyre. I should have the design finished this week so I can order the tubeset and the lugs.
It will be a little small for you but I guess you will get a good idea of what i'm aiming for when you try it out.

Si


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 Post subject:
PostPosted: Wed Aug 31, 2011 9:29 am 
Devout Dirtbag

Joined: Tue Mar 09, 2010 2:43 pm
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Location: Cheshire
No experience myself, but there has been some discussion about offset rear triangles on the CTC forum, 531colin is the user who usually pop-ups.


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 Post subject:
PostPosted: Wed Aug 31, 2011 12:31 pm 
Gold Trader / MacRetro rider
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offset rear triangles velo , you'll be going elevated next :lol:


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PostPosted: Wed Aug 31, 2011 5:10 pm 
MacRetro rider
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Joined: Fri Feb 09, 2007 4:16 pm
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Offset idea came from my tourer ctc days. What about an off set elevated stays design with Surly Moonlander 4.7" tyre clearance :lol:


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 Post subject:
PostPosted: Wed Aug 31, 2011 5:30 pm 
retrobike rider / Gold Trader
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velomaniac wrote:
Offset idea came from my tourer ctc days. What about an off set elevated stays design with Surly Moonlander 4.7" tyre clearance :lol:


Now thats going to give me bad dreams tonight :cry:

Lets just drop the offset nonsense. It's road bike talk.

Si


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