Is 75.5 crazy for a head tube

[boddunn]

Hi,
I'm thinking of getting a custom made ti frame from China but the only full carbon fork I can find that had mudguard mounts has 45mm rake. I like bikes with low trail but to get it down to 42mm it looks like I'll need to go with a 75.5 degree headtube (only seems to be BMXs with this kind of number which is a worry). What do you guys think? Will having this angle make it a dog?
If you want to openly mock me then you can see my current frame design at BikeCAD What I'm hoping to achieve is room for 28c (or maybe a bit bigger) tyres, mudguards and lowish trail.
Cheers,
Matt

[suhacycles]

What is it about low trail that you specifically like? Have you ever ridden a bike with that exact front end config?

[NBC]

what's the front centre measurement ? just be careful of toeclip overlap ! don't really want to be any shorter than 575mm !

the most i'd think about going was 74 for a big frame, and even then it'd have to be big, though mostly i'd be around 72 - 73 ish

NBC

[boddunn]

I like the quick handling and the way it feels in the corners. Can be twitchy when riding no handed but it's not so bad. I had a bike stolen a few months ago that had this kind of trail and I really miss it. I've also got a Moulton TSR which has 40mm of trail but then again that's odd in many ways so may not be a fair comparison.
Cheers,
Matt

[boddunn]

Hi Nathan,
I had noticed the toeverlap was pretty bad. Front centre is 558mm apparently. Hmm, this is a tricky. If I add 10mm to the top tube and steepen the seat tube a degree it comes out at 568mm but then I'm thinking too much of my weight will be at the front of the bike.
Hats off to the people who do this stuff for a living!
Matt

[NBC]

matt, you need to put your full name in your signature before the vsalon police get you and remove your posts !

my mercian has 42 trail (73.25 head, 58 rake) and i hate how it's so twitchy ! would be better with bags on it, but it's a race bike not a tourer

i will be changing the fork at some point in the near future

NBC

[Jonathan]

The problem is your fork. It's nothing else.

[NBC]

mr sachs would probably come in and say something along the lines of this

measure your contact points, then make the bike work around that, don't go changing your position

why not go to wound up and have them make you the fork you want ? yes they're reasonably pricey, but you'll make a far better bike than trying to use a fork not ideally suited

are you looking at the columbus hiver fork per chance ?

NBC

[e-RICHIE]

mr sachs would probably come in and say something along the lines of this
<cut>

Actually - I message-ed the OP after his first post to remind him of this:
http://www.velocipedesalon.com/forum...rum-36866.html
...and I'm waiting for compliance. No name, no thread atmo.

[boddunn]

Whoops, sorry! Forgot about that bit. Signature edited. Sorry I missed your PM Richard.
Good call Nathan, it is a Hiver fork. Unfortunately I'm pretty skint so I couldn't afford to buy another fork, I bought it as it was a great deal but forgot about this whole rake/trail thing.
Neutral handling isn't so bad, I just fancied it being quicker, maybe I should just make my life easy for myself. I've noticed you get used to whatever you ride and switching between a Moulton, a touring tandem, an MTB or road bike doesn't take long and very quickly feels normal and comfy. Obsessing over tiny details is an ever descending spiral in madness!

Matthew Dunn

[Eric Estlund]

Unfortunately I'm pretty skint so I couldn't afford to buy another fork, I bought it as it was a great deal but forgot about this whole rake/trail thing.

If you can't afford the new fork, I'd hold off before buying a new frame. You are asking a fork to dictate the design of a new frame, one that falls outside of its intended use. My suggestion would be to back up, save some more money, and get a set designed to work well together from the onset. If your Hiver is new there is a good chance you could sell it to offset your costs.

[JonoChurch]

Trail is only one factor, the "self-aligning" torque on the handle bars and becomes more noticeable as you ride faster. There's a difference between quick handling and twitchy, ie a track bike has a steep head angle but short offset so it handles quickly while being stable. It looks to me like what you're suggesting would be twitchy at any speed! From my undersranding, the only bikes that are designed with low trail are touring bikes with a long offset to stop them flopping over when racks are mounted, but it is the fork offset, not trail that dictates this

Jono Church