So, I have a pumptrack bike which is a small, and very short frame built with 26” wheels. It’s ok, but not great. I can’t get on with its ‘too high’ bottom bracket and quite longish chain stays.

I quite fancy an upgrade.

Needs to be very low stand over, for pump/jump duties, but also quite long toptube/front centre. I have monkey length arms and am too cramped on my current frame.

Would be looking for a 27.5 frame, to use with 26” wheels for pumptrack, but 27.5 for trail riding.

Tapered head tube, preferably 30.9 seat tube and happy with whatever rear axle standard. Have pro4 non boost wheels in 26” ready to go. Threaded BB, discs,

I’d prefer aluminium, but would consider steel, or even carbon.

Happy with second hand, or even new bargain.

https://www.chainreactioncycles.com/octane-one-zircus-frame-2020/rp-prod155480

Zircus doesn’t do 650B.

It would help to first of all know what it is you already have since that can eliminate frames that are shorter or the same size.

Your main problem is going to be finding a frame that does both well, a high BB allows you to pop onto the back wheel whilst stays that accommodate a 650B wheel will be as long or longer than the ones you have for your 26″ wheel.

you don’t want 27.5 for a pumptrack anyway.

Why so worried about 27,5 wheels but ok with I presume a rear mech, gears , dropper post, front brake ?

27.5 Dartmoor Hornet?

Yeah, the pumptrack version will have 26” wheels, it’s just useful to be able to run 27.5 trail wheels too, as it makes it more versatile.

Same with gears, makes it more versatile.

I currently have a Planet-x Jack flash… the new ones they just released. BB is comically high, if I want to use it as a trail frame. I can manual pretty well anyway, so don’t need a high BB particularly.

@rdoades
Is that from experience of this frame?
Never looked at these, but I’ll check em out now.

The Dartmoor Hornet is designed to have about 150/60mm travel fork. Bit long for my needs.

I’m currently using a 120mm fork

Yeah the Jack Flash was a decent enough trials frame in its day. Probably due to that BB. But based on that, how about an NS Surge Evo?

https://nsbikes.com/surge-evo,115,pl.html

Why so worried about 27,5 wheels but ok with I presume a rear mech, gears , dropper post, front brake ?

Because none of those make a blind but of difference to the handling whilst the wheels do.

That NS surge evo looks good actually. Pretty much what I was after. Not a fan of steel bikes, but would do fine for a pump/jump bike.

Because none of those make a blind but of difference to the handling whilst the wheels do.

that simply isn’t true, but carry on consuming and building a sub optimal bike for pumptrack and dirt, no problem 😀

Now, easy everyone. I’m just asking about a bike. It’s not a ‘one bike fits all’ type of question or answer.

Each to his own etc:

I’m not looking for the perfect bike, just the perfect one for me and my needs.

trail riding and pump track/jump are two totally different disciplines. You’ll compromise the bike by trying to do both.

” BB is comically high” what is its actual height?

It’ll be a massive compromise. A pump bike should be short reach, tight head angle, short back end, no gears, rock solid, short travel forks. A trail bike should have the opposite of all these things. If you want a trail bike then buy one, just accept it’ll be pretty rubbish on pump tracks

Eta.. your current frame has a 30mm bb drop or a height of around 310mm. How much lower do you want?

trail riding and pump track/jump are two totally different disciplines. You’ll compromise the bike by trying to do both.

I do appreciate this, but can only have one bike for both duties. So compromises must be made.

Eta.. your current frame has a 30mm bb drop or a height of around 310mm. How much lower do you want?

I don’t have the bike in front of me to measure, but I’m pretty certain this is not the case. From memory, the BB sits about 20 mmm (ish) higher than the rear axle. So more like 350mm high. I’d prefer it quite a bit lower than that

HighJack

guessing that bike has too long a fork on it.

My advice would be to build up a hard tail that you ride on trails first and foremost. If you want to use it on the pump track have a second set of cheap wheels with different tyres and pump the fork up really hard for pumping.

or have two bikes which is the better plan.

Exactly, which is the reason for trying to find a hardtail frame with as low a stand over as possible, but long enough to to ride for short trail rides.

The fork I have is 120mm which is what the Planet-x is supposed to have.

It’s a very first world problem I have of course, so many thanks for all the replies. I’m sure something will come up which is the right level of compromise.

Thinking about it, a last gen 26″ Chameleon (5th gen I think) can take a 27.5 up to 2.4″. Fling on some U turn forks and that could work well (they accept 120 – 140mm iirc)

that simply isn’t true, but carry on consuming and building a sub optimal bike for pumptrack and dirt, no problem

Can you explain for the benefit of all involved why a 26″ wheel is sub optimal for pumptrack but a 27.5 isn’t? DJ and pumptrack bikes have long had smaller wheels as they allow a shorter wheelbase.

As for gears and the front brake, I don’t see how they’re a problem other than you don’t really need them for the track itself. Nobody said anything about dropper posts. If you can explain how either of those can ruin a pumptrack build you should get on the World Champs circuit.

It does look higher, but I’d say that is due to the wrong forks being fitted. Put some 80mm dirt jump forks on it and it’ll be perfect

Maybe, but a 40mm reduction at the front is not gonna make that much difference too the BB. Maybe lower it by about 20mm max.

In the end, i just got a DMR rhythm and will see if that rides a little more to my liking.
With the adjustable drop-outs, i will be able to sneak in a 27.5 wheel with skinnier tyres on for some light trails, and for one of my boys to ride.