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Swoofty

+30 BB on a street trials bike!?! TMS Urbex

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Say it ain't so! Are street trials bikes going the way of pure now? +30 BB on a street bike sounds crazy, but I haven't ridden one yet. The rest of the geo is fairly standard, 985 wheelbase, 74 deg headangle. It's got that same 'between the stays' rear brake mount as the TMS Champgn too. It also comes in white apparently. If anybody rides one, let me know what it's like.

 

TMS Urbex.png

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Leonardo Mazzella rides it and does a lot of trialsy moves really well with it, seems like a fun bike to ride

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Posted (edited)

The white looks pretty good

 

Edited by Dazza1414

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The original Fourplay was +35mm...

I prefer a slightly higher BB, the +25mm on the Arcade was as low as I wanted to go. Any lower just feels too 'stable' somehow. I prefer a bike with a bit of inherent instability because that way when you harness that it makes the bike more agile, rather than having a really stable bike that you have to wrestle more. When I first went to the 'new' Fourplay after the original Mk1, I hated it at first because the big drop in BB height made it feel hard to do a lot of things on. Things like manual 180s in particular - it felt like my feet were so low/into the bike that it was hard to get the carve and preload on the go.

It's always seemed to me that the 'you need a really low BB for street' came from the way everyone used to use old MTB frames for street bikes, rather than it necessarily being the best for the intended purpose.

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On 6/7/2021 at 1:18 AM, Mark W said:

The original Fourplay was +35mm...

I had no idea the original 4play was that high. How long ago was that? (I've only been here 12 years) What was the biggest factor in changing it lower? I guess there really isn't a hard and fast definition for a street trials bike anyway. I'd say the Alias is a street trials bike, but it's way high BB and no seat so kind of a category unto itself. I'm happiest with +25 right now, but the wheelbase and head angle play a big part too.

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I've always thought people were way too obsessed with BB rise. Yes, it makes a difference, but it's not like it's the defining factor of a bike and what you can do on it. Especially when it's quite a middling amount.
If it's too high, you can counter it with a higher bar/stem. Too low, and lower the bar and stem. Up to a point, obviously. It does make a difference - but small changes from what you are used to don't make as much as people seem to think.

They also feel different between the bikes because of the radius of the wheels putting you different heights from the ground. +65 on a mod feels much less outlandish than +65 on a stock.

Certainly, some people can, but I'd be very surprised if more than 5% of riders can legitimately feel the difference between +25 and +30, once you'd added/removed a 5mm stem stacker accordingly. I certainly couldn't.
And those people that ARE so hyper sensitive to feeling the difference, I don't think it would make much difference in how they can ride after one or two to adjust.

 

I'd liken geometry obsession with mixing audio. Knowing the frequencies (aka geo measurements) can help guide you to the right area, but to make the difference you actually want you need to listen (aka ride) and see if it's right. If your kick is too boomy (manuals are unstable) it's much better to stick a peak/trough on the EQ and sweep the frequencies rather than just assuming you need to cut 125Hz because that's the theoretically correct response. Sometimes it's an underlying fundamental, or a resonance with the bass. Don't mix by numbers, because it's your ears that are going to listen to it.

5mm in the BB is only the same as switching from modern thin pedals back to something like the old shape of V12. They're thick enough that they'd put you that bit higher off the ground. Does that make it not a street bike any more? :lol: This isn't meant to read as a rant - just trying to make my point.

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I remember getting my 2011 Fourplay and it felt really low compared to the mk1. Could be making it up but I'm sure they lifted it again when they re-jigged the geo for the 2012 revision? 

Given the choice I much preferred the higher BB on the mk1 hence why I was after that or a zoot last year (and ended up with the Adamant) 

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9 hours ago, Swoofty said:

I had no idea the original 4play was that high. How long ago was that? (I've only been here 12 years) What was the biggest factor in changing it lower?

That was the Fourplay from the original one in 2007-ish through to the change in frame design in 2011. They made the chainstays shorter and lowered the BB, as well as tweaking the front reach measurement. It was just to make it a bit more contemporary, for want of a better word. I think the original Fourplay was almost a translation of the geometry of the 26" street-orientated trials bikes people were riding at the time, with the 2011 and onward versions taking what they learned from that to then improve it for a 24" wheel.

2 hours ago, aener said:

I've always thought people were way too obsessed with BB rise. Yes, it makes a difference, but it's not like it's the defining factor of a bike and what you can do on it. Especially when it's quite a middling amount.
If it's too high, you can counter it with a higher bar/stem. Too low, and lower the bar and stem. Up to a point, obviously. It does make a difference - but small changes from what you are used to don't make as much as people seem to think.

I really didn't get on with the first 2011 Fourplay I had for the reasons I mentioned above. I think us riding in different ways may make more of a difference on that though - if you're pedalling into a lot of stuff it doesn't make as much difference, but if you're not pedalling into things it does as I think the underlying 'feel'/'handling' of the bike is more noticeable then. Using the manny 180 reference I made above, doing them on the 2011 Fourplay before I modded the geo wasn't great. As before, it just felt like my feet were too low through the bike, and it was really hard to get it to turn and do what I wanted it to do. It's hard to explain, but when you could feel the balance point and the way you had to carve it, it felt like the lower BB was stopping that from happening as it basically just wanted to go in a straight line more. If I'd been cranking the 180 it wouldn't really have been a problem as the carve and pop parts are so different to non-cranked ones. That was around the time I was transitioning from pedalling into spins and hops up stuff into bunnyhopping everything so I guess that may have highlighted it more, but it's also something I notice whenever I've had a go on a Fourplay or Skye. That geo works for some people, but definitely not for me.

Changing bar and stem for a lower BB doesn't really do much to change the underlying characteristic of the bike as such, in much the same way that a higher bar/stem on a high BB bike doesn't stop it from feeling like a high BB bike - it just mitigates the change in body position a little. It's not really the body position on the bike that's the problem for me with low BBs, and if anything dropping bar height would have made it even worse.

It's definitely not the defining characteristic of a bike though, so I do fully agree with you on that bit. Much like how people used to judge bikes solely on WB, it all needs to be taken into consideration.

28 minutes ago, isitafox said:

I remember getting my 2011 Fourplay and it felt really low compared to the mk1. Could be making it up but I'm sure they lifted it again when they re-jigged the geo for the 2012 revision? 

Given the choice I much preferred the higher BB on the mk1 hence why I was after that or a zoot last year (and ended up with the Adamant) 

Correct (Y)

Original Fourplay - CS: 385mm, BB: +35mm

2011 Fourplay - CS: 380mm, BB: +20mm

2012 Fourplay - CS: 375mm, BB: +25mm

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