Frames, Bosses & Clearance?

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MacB

Lover of things that come in 3's
I have a preference for canti/v brake bosses, rack & guard mounts, generous clearances and 700c wheels. It doesn't mean I won't run skinny tyres but I'd like to have a choice to go above a certain size. For example the Mavic A719 touring rims are rated for tyres from 28-47mm, yet very few frames, excluding MTB 29ers and Cyclocross, can take tyres above 32mm including guards. 29ers are still quite new and relatively rare/expensive and Cyclocross often lack necessary bosses or comfortable geometry. The Rigida Sputnik rims are rated for 28-60mm tyres, as are other touring rims Rigida do in 700c. I understand limitations of reach for road caliper brakes and why that limits tyre and guard options. But it seems strange that you can move to canti/v brakes and yet find yourself so strictly limited on upper tyre sizes by the frame itself.

Is there a performance issue around this, would greater clearance mean slower bikes?

I know there are bikes out there, I have the Surly Crosscheck which is more an allrounder than a cyclocross frame. There's also the LHT from the same crowd. But these are strong, heavy, bikes(also far from cheap) and I was thinking more along the lines of something lighter and maybe carbon or titanium. I've been strongly drawn to the Van Nicholas Amazon but the 32mm upper limit applies. I also like the look of the Kinesis Crosslight Csix frameset, but it lacks bosses and review information seems non existent.

Then you have hybrids, in all their guises, for example I quite like the look of the Sirrus Pro 2009 model, carbon frame and all the bosses. Yet trying to find out max tyre clearance is difficult, lots of sites just say things like 'ample clearance', WTF is that? your ample, my ample? Then on the Sirrus Pro 2010 the bosses are gone, nothing for guards or racks at all. Lots of other/lower level hybrids seem to fit the bill but still give little or no info regarding clearances. Also the lighter weight ones all seem to have wheelsets that look far too delicate. Considering the myriad of hybrid bikes around I can't find anywhere that sells that style of frameset. It's always a complete bike, with some compromise, or nothing.

Am I crazy, do I want something that the demand just isn't there for?
 

Wocce Racer

Active Member
Location
In a house
It sounds like you require a custom built frame. This will give you somethings that fits you to a T, whilst a good frame builder will take into account any additions (bosses etc) that you require, wheel/ tyres and any loads you may plan to carry. The workmanship is stunning and you can choose your own colour scheme and not the boring mass produced standards.

My local builder is Roberts and I cannot praise them enough (I have two). They are not cheap, but being steel will last you forever.

http://www.robertscycles.com/
 
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MacB

MacB

Lover of things that come in 3's
thanks WR, I had looked at steel frames but I have two already, the Surly Crosscheck and Karate Monkey frames. I can't fault the Xcheck for comfort and clearance and, when the KM is built up, hope it will be the same. I was thinking more in terms of lightweight, but still versatile, and corrosion resistant. So that takes us to 953 stainless steel, carbon or titanium and some big bucks. Actually the carbon would be the cheapest of the options to get what I want. Just not sure I want a plastic bike:biggrin:

Hmmm, so custom 953 or custom titanium, therefore eyewateringly expensive.
 

Wocce Racer

Active Member
Location
In a house
Don't get me started. I was in Roberts with the missus and there was a 953 highly polished frame hanging there and I was stroking it for a minute or so. She had to drag me out! A lovely piece of metal. Ride it? Hell no, take it to bed I would!
 
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MacB

MacB

Lover of things that come in 3's
Wocce Racer said:
Don't get me started. I was in Roberts with the missus and there was a 953 highly polished frame hanging there and I was stroking it for a minute or so. She had to drag me out! A lovely piece of metal. Ride it? Hell no, take it to bed I would!

Oooohhh, mirror polished 953, I've even gone as far as getting a rough quote from Argos Cycles. I'm still leaning towards the Amazon, I'll probably never run it with bigger than 32mm tyres anyway. It just irks me that the choice is removed for no reason that I can see. Sheldon says there's no performance gain in having tight clearance frames, so it must be true:biggrin:
 

Wocce Racer

Active Member
Location
In a house
In theory the wind has less space to buffer around if clearances are small. True in a 4000 metre pursuit perhaps but on the club run, club 10 or commute???? Same as flat blade spokes: great in a cross wind!
 
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MacB

MacB

Lover of things that come in 3's
Wocce Racer said:
In theory the wind has less space to buffer around if clearances are small. True in a 4000 metre pursuit perhaps but on the club run, club 10 or commute???? Same as flat blade spokes: great in a cross wind!

Quite possibly but these are touring and cross bikes I'm looking at and are designed for use with canti brakes and sold as having bigger clearances. Taking a basic example of some popular wheelsets:-

Mavic Open Pro Rims - 622-15 - Mavic recommend use with tyres in range 19 to 28mm - a reasonable choice for a road bike. If I want a road bike then I'll happily run road calipers and skinny tyres.

Mavic A719 Rims - 622-19 - Mavic recommend use with tyres in range 28 to 47mm - a good reputation as a bomb proof touring rim
Rigida Sputnik Rims - 622-19 - Rigida recommend use with tyres in range 28-60mm - a good all round reputation, touring, commuting etc, and half the price of the Mavics.

There doesn't seem to be a lot in the way of rims in between the 15 and 19mm widths. So you buy a touring or cross bike, it comes with brake and rim capability for tyres from 28mm up to 50mm and beyond. Yet frame limitations mean that, in reality, you're only gaining that little gap from 28-32mm. As in the Amazon, canti brakes, Rigida Andra rims rated 28-62mm and a max tyre of 32mm.

A Big attraction of titanium or 953, for me, is the resistance to corrosion, so a true year round bike. Have two wheelsets, whack on the Open Pros for the Spring/Summer/Autumn and then the A719's for Winter. Run skinny slicks or fat knobblies with studs, etc, etc. We're only talking an additional 2-3cm of clearance here.

I think I'm starting to get a complex about this:biggrin:
 
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