Custom Built Aluminium Mod Frame

[flipkickbs]

Fabricator.

That looks heavy and very breakable. Nice logo though

Ian

Edit: As if magura setup is not already fiddly enough, let alone having to set it up inside your frame!!!!

Edited March 29, 2006 by flipkickbs

[Guest]

Your realling winging it arn't you?

Like I said before, you might be able to weld but will you be able to heat treat it after you've done the welding?

[TheFabricator]

Not going to use a copper silicon alloy but even if I was I can get it heat treated anywhere by next day.That aside what do you think of a higher BB.I can accept people might not like the enclosed frame allthough I think it looks clean.My sketch has a BB drop of -100 mm. Its easy to make but I would need a pro rider to test the geometry even if it breaks id be happy to see how an extreme design geometry performs.Were talking R+D here not writing an order out for 10,000 frames.

[Mark W]

Seriously, enclosed chain and brakes won't ever sell you frames. If a chain breaks riding trials, you really are in the shit, so not being able to check it (and even install it?) without loads of hassle would be a bitch. A lot of mod riders use FFW too, so not being able to check or service the freewheel easily would be a bit arse. 4-bolt spacing for Maguras is also aaaaround 98-105mm wide, meaning the brake will stick out - say - 15mm from each side of that. That means that your design would have to be over 135mm wide around the brake mounts, which would mean you'd also need to make it with a wider BB. Wider BB shells with standard rear hub spacing = even worse chainlines than mods have now, putting a lot more strain on all the drivetrain.

Benc has released a mod frame with +90mm BB height, by the way, so you might as well sit tight and see how that goes, basically. Market research 'n' all that. No-one seems interested in it though, seeing as +60mm is still fairly 'extreme' on a mod, so adding 40mm to that will make it a dog to ride. Mods are rear-wheel happy anyway, so that'd just make them too jittery on the back wheel, not to mention hard to get the power down for gaps, too. You may also need to make a higher-rise stem to go with it too if the BB's that high. If you notice the trend in stocks with high BBs, they tend to have higher-rise stems to go with them...

[TheFabricator]

ok thanks OMB i'll take on board your constuctive critiscism.I thought they need to be rear wheel happy, getting the bike instantly on the back seems like the favourite tecnique but i can understand the problem getting the power down for a gap which seems bad. when I say " enclosed design" I dont mean you cant see the chain its just that its all on the inside of the deep chain stay.It can still be viewed from above or below the frame.Point taken with the width of the Maguras I suppose I could compromise and have the head of the cylinders sticking through the frame. Could always use a rear disk which would be much narrower but I understood a lot of riders still prefer a rear magura set up. Have you got a link to Benc Bikes.

[Mark W]

Basically, the problem with gapping is that to gap, you lower the front, apply the power, then in one movement throw your bodyweight to the bars and kick the back end in front. When you have a higher BB, to lower the BB the same amount for the correct preload tends to mean you have to drop it lower, and also when you kick it tries to look out very easily. Stability on the back wheel is crucial too, so getting the centre-of-gravity when you're on the back wheel in a correct alignment with the BB and so on is crucial. +100 would just be a bit too much, IMO.

I don't have a link to Benc Bikes, sorry. On Observedtrials.net they've posted some pics up of their frames, but they're much like the Vario Styx frame, only a 20" version (see www.tartybikes.co.uk for pics of the Styx).

Don't forget about the cross-over when you're talking about Maguras too, 'cos you'll need clearance for them too.

[TheFabricator]

Ok. What about replaceble bolt in down tube and chain stays to repair damage.

[Greetings]

370 makes them 5mm shorter than a Python and 5-7mm longer than a Levelboss, Zip, T-Pro, etc...

You need a half-link chain on a 18:12T drivetrain when running a 370mm chainstay, otherwise the chain will be loose.

Think about it - the 363mm stays is X chain links, where as 375mm stays is X+1 link. You can't tighten a chain on 370mm without a halflink.

[TheFabricator]

what about a twin 3/32 chain set up for you stock lads.

[LukeDraisey! :)]

single tube frames wont work, just ask giant they bought one out and it died

Ben

ooooo.... i wanna see.

[fredrico]

ooooo.... i wanna see.

Edited April 4, 2006 by fredrico

[Mark W]

You need a half-link chain on a 18:12T drivetrain when running a 370mm chainstay, otherwise the chain will be loose.

Think about it - the 363mm stays is X chain links, where as 375mm stays is X+1 link. You can't tighten a chain on 370mm without a halflink.

It's not like 370 is a fixed point though, it's just that that's where the wheel is slammed. You'd probably have to yank it back in the drops a bit, but there we go...