# Bromptons Downhill



## steveindenmark (18 Sep 2018)

Having never ridden a Brompton and now got one on order What speeds would you expect downhill. Sorry if that sounds a dumb question.


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## Biff600 (18 Sep 2018)

Surely would depend on how fast you are pedalling, incline of the hill etc ??


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## ianrauk (18 Sep 2018)

Fast


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## alicat (18 Sep 2018)

And how much you weigh - damhikt.


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## welsh dragon (18 Sep 2018)

On 20 inch wheels going down a steep hill is interesting to say the least. Going down one hill near me, i can clock 33mph. I would hate to go down that on 16 inch wheels. 

As an above poster said bloody fast.


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## sheddy (18 Sep 2018)

What is the worst thing that could happen ? 
Just keep those buttocks firmly clenched...


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## cosmicbike (18 Sep 2018)

It feels faster than it really is. I bottled it at 20 mph, but then I don't ride mine very often. More so now since Mrs CB seems to have taken ownership for commuting duties....


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## rogerzilla (18 Sep 2018)

I've taken one up to about 45mph. They're a bit scary because, if you do get shimmy (I didn't) you can't damp the oscillation with your knees!


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## NotAnother Cyclist (18 Sep 2018)

I've got mine up to 39mph. Pretty hairy!


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## TheDoctor (18 Sep 2018)

42mph for me. Surprisingly stable at that speed.
Not sure I'd fancy going too much faster, but if you sit bolt upright you've got one mighty air brake going on.


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## steveindenmark (19 Sep 2018)

I was tired when I posted What I meant was do they feel as safe as riding a df downhill fast.


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## ianrauk (19 Sep 2018)

Yes. But others may feel different.


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## bikegang (19 Sep 2018)

And depending on how brave you are... Hinge failure images always keep me slower than on my MTB ...


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## Illaveago (19 Sep 2018)

Is there a Land Speed Record for riding a Brompton ?


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## Joe Brom (19 Sep 2018)

I'm not a fan of really getting cooking on a Brompton. It's not so much that it feels unstable as that you know if the front wheel kicks out of line, it's probably not coming back like a big wheel would. It rolls fast enough to get me around, so I don't mind its limits.


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## Kell (20 Sep 2018)

I've had mine up to 44 mph on a pretty steep hill near me. In fact, I do it every morning as it's part of my commute.

I do have slightly wider bars on mine and it's much more stable than you'd think. 

However, the wheels don't generate anything like the gyroscopic forces that bigger wheels do so there's no way it feels as stable as a 'proper' bike.

For what it's worth, I've been down there on my road bike and also on a full size Dahon and I didn't go any faster on either of those (I have the aerodynamic abilities of a beachball) but they definitely feel more stable.

The biggest worry with that sort of speed (on any bike) is what you do if you need to slow down quickly. I only go that fast on that hill when:


visibility is good
it's not raining
traffic is light



View: https://www.youtube.com/watch?v=1wNkVZltMfw


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## 12boy (20 Sep 2018)

I find Kell's video terrifying. A year ago I missed seeing a crevice and found myself with a pelvis broken in 3 places. As with riding in poorly lit conditions, I don't like to go faster than I can see. On a known road with good visibility I can go 40 without feeling any shimmy, especially if I have some weight in the front bag. However, unexpected gravel, ice or other hazards could leave you in a world of hurt.


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## Drago (20 Sep 2018)

Even Evel Knieval turned down a million quid to ride a Brommie downhill at 50 MPH. Too dangerous, he reckoned


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## CopperBrompton (22 Sep 2018)

40mph is the fastest I've been yet, but that was the limit of the hill and the engine rather than the bike. It felt fine to me at that speed.


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## kais01 (21 Apr 2019)

if you angle the m handlebars forward, steering will get heavier and stability increase. s handlebars are already in a more forward position.

its equivalent to fitting a longer stem on an ordinary bike.

wider bars make it easier to handle gyroscopic forces, jerks and self-steering, but the power of all three are minimal on a brompton because of the small wheels. already ordinary brompton bars are overly wide considering this.


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