Frame geometry - understanding how it will ride

tailwindhome

Wrath Rob wrote:

So, I'm currently in the process of getting a custom frame made. Something British in titanium that should be a forever bike that meets my commuting and winter requirements. And that runs disc brakes .

There was a poster on here who was setting up his own company having designed his own frame exactly as you describe + running a hub gear (Alfine maybe?)

Can't remember his name now......

tgotb

TailWindHome wrote:

Wrath Rob wrote:

So, I'm currently in the process of getting a custom frame made. Something British in titanium that should be a forever bike that meets my commuting and winter requirements. And that runs disc brakes .

There was a poster on here who was setting up his own company having designed his own frame exactly as you describe + running a hub gear (Alfine maybe?)

Can't remember his name now......

That was Roastie iirc. Wasn't the bike called "Such"?

veronese68

I'm surprised that WR is that much of a freak. Looked fairly normal size to me. Still, sounds like a good idea.
Did you read the follow up piece about disc brakes here. It seems cables are possibly a better idea if you use incompressible outers.

Wrath Rob

Veronese68 wrote:

I'm surprised that WR is that much of a freak. Looked fairly normal size to me. Still, sounds like a good idea.
Did you read the follow up piece about disc brakes here. It seems cables are possibly a better idea if you use incompressible outers.

I hadn't either until I had the bike fit. It showed that my hip-knee to knee:ankle ratio put me in the top 5% of the population, i.e. I have very long upper legs compared to my calves. It explains why I have such problems with budget airline seats. In terms of a bike fit it means that (as I'm finding out) I need a longer top tube and slacker seat tube angle than most bike manufacturers provide to put me further over the back wheel and therefore in the right position. The alternative is the short stem, extreme set-back and saddle rail combo that I ride now. Both get me to the right place, one is more of a compromise than the other. Thanks for the piece on the brakes, off to digest now.

@TGOTB: Not going to the HC as I've got a pretty full day and then Ride Around London on Sunday means this weekend is out. Maybe next weekend if you're around?

Anonymous

TGOTB - Ed F is going to that. Look for the repaired S works.

supersonic

It explains why I have such problems with budget airline seats. In terms of a bike fit it means that (as I'm finding out) I need a longer top tube and slacker seat tube angle than most bike manufacturers provide to put me further over the back wheel and therefore in the right position.

Problem here is if you have a short upper body and reach, like I do - the longer top tube combined with a slacker seat angle and/or set back means the reach is too long! But as I do more MTBing than road, the actual position that is 'right' is rather subjective, the whole 'knee/plumbline' thing is generally not used.

tgotb

coriordan wrote:

TGOTB - Ed F is going to that. Look for the repaired S works.

Excellent! I'm pusher-off, so I can have a good look at the repair :-)

Levi_501

Would it be worth visitng that place in Holborn (I see you are in London) Cycle Fit or soemthing. They specialise in the relationship between human and machine.

supersonic

Levi_501 wrote:

Would it be worth visitng that place in Holborn (I see you are in London) Cycle Fit or soemthing. They specialise in the relationship between human and machine.

Can be. But in my experience you can visit 5 different places and have 5 different results.

First.Aspect

Rob - the geometry changes you are talking about put you right into cross bike territory. Cross bikes tend to have lightly higher front ends and bbs, but from personal experience, it doesn't really matter. The main issue (for stock frames) is getting a road bike seat to bar drop. Manufactuers of cross bikes (and sportive bikes) to rather like to tell us what position we need to be riding in, and they do bang on so about flex we never really noticed in parts that don't really flex. Anyway.

I've just gone for a Ti Lynskey. Ride is absolutely fantastic, but it has slightly steeper tube angles than many and other than the bb height and the trail is pretty much road geometry. This places me nicely forward over the cranks, which I like. Unlike my Salsa, which felt more like a mtb.

Really think twice, and then think a third time, before being told to sit further back from the bb; it feels like cycling up hill all the time. I know the bicycle fit specialists tell you that you are set up all wrong (if they didn't then turkeys and xmas spring to mind) but are you sure, I mean absolutely sure, that you want to hard wire a new geometry into your new bike?

As regards forks, beware - that Enve doesn't have mounting for guards. Or even a drilling through the crown to fix guards to. Fine if you commute in California. Less good for Scotland. You are somewhere inbetween.

Whoever spoke about fork rake is correct. It will change the steering feel, in exchange for a change in stability. The same applies to trail. I've got to be honest, unless hammering down from Lowther summit, I can't say it mattered - even when comparing a pointy road bike with the Salsa. In a straight line it doesn't matter at all.

I have to say, if you are going for discs and a commuting bike, I wonder why you are so fixated on it being essentially a road bike with discs. Why not allow yourself a bit more tyre clearance? I have 25c's on at the moment, but I suspect I'll mount some knobbly 32c's at some stage. It doesn't look too "gappy" at the moment, and I have the option to go properly off piste.

There is some tosh spoken about discs. I've now tried mechanical and hydraulic converters and of course I'm familiar with normal road brakes. The Hope V-twin commuter is a big step up from Avid BB7's. But the "correct" reason to get discs is rim longevity through crappy months and possibly consistent braking (although an experienced roadie wouldn't have any issues anyway, so this is overstated). Don't let fork strength and so on. There are plenty of light mtbs out there now which don't spontenaously disintegrate and I'm sure manufacturers have figured out how to deal with the forces by now. The forces from disc brakes are new to road/cross, but they really aren't new.

Also don't let the added weight bother you too much either. When you are knackered and have a bag on your back cycling home, trust me its you, not the bike.