Author Topic: Bike work stand to use with Brompton  (Read 782 times)

Bike work stand to use with Brompton
« on: March 13, 2018, 05:06:03 pm »
Can anyone recommend a work stand to use with a Brompton - looking online Halfords have one for £50 . does anyone know if the jaws open to, (it is 45mm) diameter Brompton tube

Recommendations would be appreciated

Torslanda

  • Professional Gobshite
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Re: Bike work stand to use with Brompton
« Reply #1 on: March 13, 2018, 05:44:47 pm »
I have the 30 quid Aldi/Lidl stand (one or the other, can't remember) and, come to think of it, I've never tried a Brommie in it. So not much help really.

Looking at the Halfrauds webpage it looks very similar. If it can't clamp the main frame tube it can certainly clamp the seatpost. They're a touch 'bouncy' and the clamps that adjust the stand are plastic around mild steel tubing although the frame clamp itself is quite secure.

What tends to happen with 10kg+ bikes is that the clamp holds the frame/seatpost securely but, unless it's perfectly balanced, the bike hangs nose or tail down. Depends on where you clamp it. 

Will be suitable for most jobs, except possibly bottom bracket removaland a bargain at that money.
VELOMANCER

Well that's the more blunt way of putting it but as usual he's dead right.

Re: Bike work stand to use with Brompton
« Reply #2 on: March 13, 2018, 07:18:26 pm »
I agree, clamp the seat post.

Re: Bike work stand to use with Brompton
« Reply #3 on: March 13, 2018, 07:43:03 pm »
I have to use the seat post on my Moultons on my Minoura 4000 stand. The clamp can be rotated to counter the drooping.

Re: Bike work stand to use with Brompton
« Reply #4 on: March 13, 2018, 08:49:47 pm »
I think that I read somewhere that Brompton do not recommend clamping the seat post

Re: Bike work stand to use with Brompton
« Reply #5 on: March 13, 2018, 09:35:41 pm »
Probably best not to clamp it near the top if extended; just above where it enters the seat tube should be fine.

Torslanda

  • Professional Gobshite
  • Just a tart for retro kit . . .
    • John's Bikes
Re: Bike work stand to use with Brompton
« Reply #6 on: March 13, 2018, 10:36:48 pm »
I have to use the seat post on my Moultons on my Minoura 4000 stand. The clamp can be rotated to counter the drooping.

May be true of the Minoura. Lidl stand just droops...
VELOMANCER

Well that's the more blunt way of putting it but as usual he's dead right.

Re: Bike work stand to use with Brompton
« Reply #7 on: March 14, 2018, 11:03:30 am »
Probably best not to clamp it near the top if extended; just above where it enters the seat tube should be fine.

Brompton do not recommend that you use the seat post

https://brompton.zendesk.com/hc/en-us/articles/203295431-How-do-I-secure-the-bike-in-a-workstand-

I suppose the question for me is the Halfords one at £50 or the Park Tool PCS-9 at £100

LittleWheelsandBig

  • Whimsy Rider
Re: Bike work stand to use with Brompton
« Reply #8 on: March 14, 2018, 11:50:22 am »
So it is ok to clamp the seatpost at any location to put the saddle at the right height but the seatpost isn't strong enough to cope with a workstand clamping it? I call bullshit.
Wheel meet again, don't know where, don't know when...

grahamparks

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Re: Bike work stand to use with Brompton
« Reply #9 on: March 14, 2018, 11:56:07 am »
Note he says "*I* don't recommend" not "we" - taking this as official Brompton policy is a bit of a jump.

Re: Bike work stand to use with Brompton
« Reply #10 on: March 14, 2018, 12:42:13 pm »
Note he says "*I* don't recommend" not "we" - taking this as official Brompton policy is a bit of a jump.

my deepest and most humble apologies ........... I will re-phrase my comment

"the guy who works for Brompton and who Brompton feature in most of their "maintenance" videos does not recommend that the Brompton be clamped by the seat post when placed in a work stand"

what are you on? - next time you ride your Bike don't forget to put the seat, (or should I say saddle to keep you happy?), on the seat post before you sit on it.

Re: Bike work stand to use with Brompton
« Reply #11 on: March 14, 2018, 01:32:04 pm »
Does he say why?

It might just be that he's had issues with knocking the clamp open, or the bike rotating in the clamp (since the seatpost is shiny and slippery). Clamping on the frame may hold it more securely.
<i>Marmite slave</i>

Re: Bike work stand to use with Brompton
« Reply #12 on: March 14, 2018, 02:29:43 pm »
Does he say why?

It might just be that he's had issues with knocking the clamp open, or the bike rotating in the clamp (since the seatpost is shiny and slippery). Clamping on the frame may hold it more securely.

reasons: safety and stress on seat post .........

LittleWheelsandBig

  • Whimsy Rider
Re: Bike work stand to use with Brompton
« Reply #13 on: March 14, 2018, 02:51:51 pm »
Do you mean the seatpost that is rated to carry riders of approx. 100kg weight at full extension over road defects like potholes?
Wheel meet again, don't know where, don't know when...

grahamparks

  • London N19
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Re: Bike work stand to use with Brompton
« Reply #14 on: March 14, 2018, 03:18:57 pm »
This has a very strong whiff of received wisdom to me, of something once decreed by a respected Brompton employee - possibly in the distant past - and followed by everyone else with the justification retrofitted around it. Brompton is exactly the kind of chaotic, eccentric organisation with lots of new hires where this sort of thing happens.

(Plus I do think the choice of words is important. "I recommend not" is a very long way from "Brompton recommends never", and this advice appears to exist in this video and nowhere else)

Re: Bike work stand to use with Brompton
« Reply #15 on: March 14, 2018, 04:02:17 pm »
I suppose it might be to discourage clamping by the seatposts and then swinging on it like a chimp to remove the BB, but then I can't imagine clamping it by the frame would be that much better.

Regarding workstands, I've got the Park PCS-10, which is basically a PCS-9 with.a posher clamp, and am pretty happy with it. It's rather heavy and doesn't fold particularly small, and there's enough flex that I wouldn't want to do anything involving big torques with it, but that's common to all clamp-type stands IME. For general fettling, gear adjustment, etc. it works well, and can be found online for a fair bit under the RRP.

Re: Bike work stand to use with Brompton
« Reply #16 on: March 14, 2018, 05:16:41 pm »

Regarding workstands, I've got the Park PCS-10, which is basically a PCS-9 with.a posher clamp, and am pretty happy with it. It's rather heavy and doesn't fold particularly small, and there's enough flex that I wouldn't want to do anything involving big torques with it, but that's common to all clamp-type stands IME. For general fettling, gear adjustment, etc. it works well, and can be found online for a fair bit under the RRP.

Thanks, just what I needed - plus a few recommends on my Motor Bike Forum for the Park Stand - I'll grab a PCS-9 in a few weeks when we are next in the UK, (cheaper than France) and I think the PCS-9 goes up to 70mm

handcyclist

  • watch for my signal
Re: Bike work stand to use with Brompton
« Reply #17 on: March 14, 2018, 07:21:32 pm »
So it is ok to clamp the seatpost at any location to put the saddle at the right height but the seatpost isn't strong enough to cope with a workstand clamping it? I call bullshit.

This.^

The max rider weight is specced by Brompton at 110KG but the seatpost isn't good enough to hold up a 12KG bike? BS
Doubt is is not a pleasant condition, but certainty is absurd.

Re: Bike work stand to use with Brompton
« Reply #18 on: March 14, 2018, 08:13:00 pm »
The forces would be different. The rider's 110kg would go, mostly, straight down the post to the frame. If the clamped bike isn't balanced around the seat post (and there's no particular reason why it should be, especially if the rear triangle is swinging around), there'll be a twisting force on the base of the seat post.

I'd still have thought it would be OK if the clamp were at the base of the post. The moment about the fulcrum at the base, and therefore the stress, would increase the further up you placed the clamp.

You'd still hope, I think, that it would be strong enough, but it's not quite as straightforward as it seems.

Kim

  • 2nd in the world
Re: Bike work stand to use with Brompton
« Reply #19 on: March 14, 2018, 08:28:27 pm »
Surely it's just arse-covering wrt people doing up the clamp bastard tight and crushing/scoring the seatpost?
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LittleWheelsandBig

  • Whimsy Rider
Re: Bike work stand to use with Brompton
« Reply #20 on: March 14, 2018, 08:29:17 pm »
A rider's weight applies a significant bending moment to the seatpost due to the seat tube angle. A seatpost isn't predominantly designed for an axial force. Run the numbers and see for yourself.
Wheel meet again, don't know where, don't know when...

Re: Bike work stand to use with Brompton
« Reply #21 on: March 16, 2018, 06:37:17 pm »
Pump Stand by 1nterceptor, on Flickr