Bike geometry/ Height.

[JamieP]

Hi all.

Ive recently bought a Rockman Manus, after stopping trials since 2009.

I wanted to ask if people could give some insight into geometry, as opposed to height (I’m 6ft). I believe the bike is 1010mm WB, +80mm BB rise, the stem is 150mm with 30° rise, but I am unsure of the cranks length - they are ISIS Try-all silver cranks if that narrows it down.

I feel quite cramped whilst on the back wheel. I never had this issue before and I’ve always ridden mods (I used to ride a T-Pro, and then an Adamant A3). I assume that a longer and higher rise stem would help rectify this, although I cannot find any, due to the fork tube being cut angled, and cutting this down to make it flat would be counterproductive for what I’m trying to achieve.

I think that different bars with a higher rise and tilted forward could also help, although I am not entirely sure.

Other than changing the frame, are there any other things that can be altered beforehand, and how does BB rise effect the feel of a bike, as I’m sure my previous bike never had +80mm rise.

Thanks in advance.

[Matt24.]

Hey. Reading the message you are looking along the right lines to help lengthen the reach to help feel a bit less cramped. Either a longer stem or high risers will help however I would maybe go for the riser bars first as you can play with the angle to give you more length or not. If you want a more upfront feel in the bars to help feel more neutral when on two wheels you can always lengthen the stem and roll the bars back for the desired effect. It is definitely cheaper to play with a set of high risers and a stem than trying new frames etc and it can make a vast difference to how it feels even with a few cm’s difference. 

[JamieP]

8 minutes ago, Matt24. said:

Hey. Reading the message you are looking along the right lines to help lengthen the reach to help feel a bit less cramped. Either a longer stem or high risers will help however I would maybe go for the riser bars first as you can play with the angle to give you more length or not. If you want a more upfront feel in the bars to help feel more neutral when on two wheels you can always lengthen the stem and roll the bars back for the desired effect. It is definitely cheaper to play with a set of high risers and a stem than trying new frames etc and it can make a vast difference to how it feels even with a few cm’s difference. 

Nice one  It all makes sense logically. I need to find a suitable stem, and a different set of bars and have a play. 

Just being back on a trials bike feels weird, so I’m trying to make it feel ‘normal’ before getting completely involved lol.

[Mark W]

Your old bikes were around the +50-60mm BB height mark, and although +80mm is 'only' around 20mm more, that's quite a change in height!

Going higher with the bar and stem will definitely help, especially for your height.  It helps neutralise some of the over-the-bars feeling you get with higher BB bikes, but it'll never make it feel quite like your old bikes simply because your centre of gravity is lifted too, so it'll inherently feel different.  

In fairness, once you're used to them the new generation mods are super capable, they just take a bit of getting used to.  I used to ride the old Levelboss-style T-Pro and loved it, but then rode a few higher BB mods and eventually got to grips.  Still wouldn't ride one above the height yours is now,  but horses for courses

EDIT:  Oh, forgot to say - I'm around the same height as you, and always ran 180mm stems.  I wasn't doing all the super tech front wheel stuff people are doing now so a slightly lower front will probably work best for that, but if you want to try and get somewhat close to the feel of your old bike, a Jitsie, Trialtech or Clean Forged stem around the 180mm mark would be a good call.  Just check you've got enough steerer to change stems first.  If your current one is 150mm x 30° it's probably a sloping top cap stem, so switching to a flat top cap stem might be difficult unless you've got some spacers you can play around with.

[Matt24.]

And for comparison sake. Unlike you and Mark am vertically challenged at just under 5,6” and run a 150mm on the alias I sometimes mess about on!!

[JamieP]

2 hours ago, Mark W said:

Your old bikes were around the +50-60mm BB height mark, and although +80mm is 'only' around 20mm more, that's quite a change in height!

Going higher with the bar and stem will definitely help, especially for your height.  It helps neutralise some of the over-the-bars feeling you get with higher BB bikes, but it'll never make it feel quite like your old bikes simply because your centre of gravity is lifted too, so it'll inherently feel different.  

In fairness, once you're used to them the new generation mods are super capable, they just take a bit of getting used to.  I used to ride the old Levelboss-style T-Pro and loved it, but then rode a few higher BB mods and eventually got to grips.  Still wouldn't ride one above the height yours is now,  but horses for courses

EDIT:  Oh, forgot to say - I'm around the same height as you, and always ran 180mm stems.  I wasn't doing all the super tech front wheel stuff people are doing now so a slightly lower front will probably work best for that, but if you want to try and get somewhat close to the feel of your old bike, a Jitsie, Trialtech or Clean Forged stem around the 180mm mark would be a good call.  Just check you've got enough steerer to change stems first.  If your current one is 150mm x 30° it's probably a sloping top cap stem, so switching to a flat top cap stem might be difficult unless you've got some spacers you can play around with.

Thanks.

I did think Adamant was around 60mm BB rise, I’m surprised I remember haha. Funnily I’ve just found an Adamant A3 frame (Long) for a good price, and am going to build a budget bike up too. That’s the shape T-Pro I used to have too, my first bike back in the day.

Yeah, the top cap is an angled one, I couldn’t find a stem that was any longer than the one I have.