Object Posted October 25, 2011 Report Share Posted October 25, 2011 (edited) Okay, I bought into the trials world last year (I'd had a brief dabble back in the mid to late 90s but moved onto BMX shortly there after). Trials wise I've been riding a mod but still riding a lot of BMX too. It has to be said that however much I like trials, the BMX is the default fun bike as it's much more versatile. What I want is a bike I can ride street on in a similar vein to what I'd do whilst out on the BMX (Sans pegs of course) but still able to cope with some of the trials stuff . Those of you purely into TGS or competition may want to close the thread now. I don't like Aluminium frames, I've tried but they're just not my cup of tea. Having discounted a British builder I've settled on getting a 4130 marino frame built (Hell I've been riding 4130 for 15 years, why change now?). As I'm going custom I may as well build go for something a little different and fit for (my) purpose. I've been playing around with geometry for a custom build for quite a couple of weeks and come up with the following. WB 985, Stays 365, BB +23 (Don't ask), Head Angle 75 This is a weird mix between what I'm used to on the BMX, the NS Capital and the 2011 Fourplay. Does this sound about right for something short and streety whilst capable of some trials? I ask mainly as it's a mile away from anything I've seen before (Although I realise the Skye which has just come out has a similar WB so I'm a touch less nervous that I was of making this happen. To whom ever writes it as a response first: Yes, well done; "Get a BMX" was an obvious reply, if you've read this far you've surely realised that I have one and want another bike in addition to the others I already own. Edited October 25, 2011 by Object Quote Link to comment Share on other sites More sharing options...
aener Posted October 25, 2011 Report Share Posted October 25, 2011 Just to check... Is this to be a 24", or a BMX/Mod hybrid? I've been thinking about streety but still trialsy mods recently, and I think 985 would probably be a tad short. Will give a more comprehensive response when I know if we're talking about the same thing or not Quote Link to comment Share on other sites More sharing options...
Object Posted October 25, 2011 Author Report Share Posted October 25, 2011 Just to check... Is this to be a 24", or a BMX/Mod hybrid? I've been thinking about streety but still trialsy mods recently, and I think 985 would probably be a tad short. Will give a more comprehensive response when I know if we're talking about the same thing or not Can't believe I managed to miss that piece of information out. It's for a 24. Quote Link to comment Share on other sites More sharing options...
Luke Rainbird Posted October 25, 2011 Report Share Posted October 25, 2011 The short rear end will not only lend itself to popping up nicely, but will give a bit of trialsiness back where you lose it on the wheelbase. Obviously something a tad longer would sit on the back wheel and hop around all day long rather nicely, but that's not what you're after Danny manages to throw some pretty tidy trialsy stuff into his riding on the Skye which isn't far off what you've got written down, so it will be far from completely gone. From what you've described, this should meet your needs pretty nicely. The only thing I would double check is the chainstay length on the NS/a 24" BMX (something like the Model C Plus 4 maybe) to make sure it's not going to be too short for that. If it is, just bump it up a tad and away you go Quote Link to comment Share on other sites More sharing options...
JD™ Posted October 25, 2011 Report Share Posted October 25, 2011 The short rear end will not only lend itself to popping up nicely, but will give a bit of trialsiness back where you lose it on the wheelbase. Obviously something a tad longer would sit on the back wheel and hop around all day long rather nicely, but that's not what you're after Danny manages to throw some pretty tidy trialsy stuff into his riding on the Skye which isn't far off what you've got written down, so it will be far from completely gone. From what you've described, this should meet your needs pretty nicely. The only thing I would double check is the chainstay length on the NS/a 24" BMX (something like the Model C Plus 4 maybe) to make sure it's not going to be too short for that. If it is, just bump it up a tad and away you go This, basically. 370mm stays in my opinion and you've got exactly what you want. Loving the steep head angle Quote Link to comment Share on other sites More sharing options...
Ross McArthur Posted October 25, 2011 Report Share Posted October 25, 2011 WB 985, Stays 365, BB +23 (Don't ask), Head Angle 75 Sorry but ive got to ask! +23? Ive heard stories of frame builders getting geos slightly out. Would you be worried if it came and it was 20 or 25? Otherwise, it looks like a cool little project. Quote Link to comment Share on other sites More sharing options...
Object Posted October 25, 2011 Author Report Share Posted October 25, 2011 Luke, good plan, the Model C is 14.6" so works out as 370.84, I'm going horizontal dropouts so that's within the realm of adjustability. JD, as per the above if you pulled the 370 figure from the air I'm impressed. Ross, you just had to ask...a couple of millimetres either way isn't going to matter as I'm not that good, but I like the number 23 and it saves me making a decision between 20 or 25. Quote Link to comment Share on other sites More sharing options...
Mark W Posted October 25, 2011 Report Share Posted October 25, 2011 Sorry but ive got to ask! +23? Ive heard stories of frame builders getting geos slightly out. Would you be worried if it came and it was 20 or 25? Otherwise, it looks like a cool little project. I've heard of frame builders getting geo more than "slightly" out Regarding the geometry, for the CS length it's definitely worth building it around the gear ratio you want to use. I really don't understand why people who know they want to use ratio X set their CS up to run length Y just because it's a "normal" number. For example, I know I like using 22:15 so if I was going custom I'd want something like a 365mm CS length as I'd be able to use my favoured gear ratio without having to mince around with tensioners or anything like that. Speaking from my BMX experience, having a frame built a ratio you like rules. So much less hassle! BB height sounds good. I raised the BB height on my 2011 Fourplay frame and it worked out as being around 25-27mm (can't remember exactly what it was) and it feels pretty sweet for most things. The head angle sounds pretty good, although make sure your pretty firm about getting it like that. I don't think I've ever known anyone who's ordered a custom frame with a specific head angle actually getting what they ordered. It seems like not many frame builders really put much emphasis on making sure it's right, when for me it's a pretty key feature of a frame - especially for a streety 24. Anything at speed, or carving into/out of spins makes your head angle pretty important. I've ridden a bike that had the head angle made too steep (it was around 76°), and it pretty much ruined what was otherwise a really nice frame. Do you have any sort of idea what the reach of that frame would be? It'd be interesting to know what it'd work out as. If it was on that drawing and I missed it then apologies for that The WB sounds really short, but if you've got a steeper head angle then that might distort it quite a bit. Quote Link to comment Share on other sites More sharing options...
Object Posted October 25, 2011 Author Report Share Posted October 25, 2011 The dirty mathematics suggests 658.57. But we can assume that's a a little out either way. I should point out I intend on running a nice short stem (50mm) with some super high bars but that may change depending how it feels to ride once built.The head angle sounds pretty good, although make sure your pretty firm about getting it like that. I don't think I've ever known anyone who's ordered a custom frame with a specific head angle actually getting what they ordered. It seems like not many frame builders really put much emphasis on making sure it's right, when for me it's a pretty key feature of a frame - especially for a streety 24. Duly noted! Quote Link to comment Share on other sites More sharing options...
Mark W Posted October 25, 2011 Report Share Posted October 25, 2011 Yeah, I've got a 70mm with a 73° HA, and I think if I went up to 74.5-75° I'd want to go to something like a 50mm. I run about a miles-worth of stackers and High Rise bars, so yeah, high and short = the way! Quote Link to comment Share on other sites More sharing options...
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