Lowering the bike?

[Shurup]

Is it possible to lower the seat height by 10 cm or so? Thinking Ninja 250 or 300 or possibly cbr250.

Changing the tires and rims will drop it down a bit but I wouldn't want to put too small tires on it. Any other options?

[Neilly]

I know they do a lowering option for the CRF250L....CRF250M lowered....enough?

[Shurup]

Crf is a dirt bike, its way to tall to begin with.

The bikes I mentioned, Kawasakies, seat height is 790 mm dropping it down to 700 will do. It's for a GF who just can't reach the ground. She can ride my chopper which is about 650 mm or so, and her brother's Chinese dirt bike which is a bit taller but she still can reach the ground, I will measure its seat height tonight.

Edited August 2, 2013 by Shurup

[Gsxrnz]

I don't know the specific bike, but have lowered bikes before. Depends why you want to lower it - handling or comfort.

Lowering by 2-4 cm will not alter the handling too much but will generally make a bike turn in quicker at speed. You can lower the front by say 2-4cm and no need to lower the rear. but you won't get the lower seat height you want.

Lowering as much as 10cm is actually quite a bit. You can drop the triple tree down and have the forks come through, provided there's no obstruction. If the suspension is a single you can fit "dogbones" to reduce the height. If it's double rear swingarm mounted, you can buy smaller units.

But...10cm is a lot and if you achieve it all through suspension and tyre height you'll find the bike very different to handle. Try a combination of 2-4cm on the suspension, and taking some foam off the seat, plus lower profile tyres and/or smaller rims.

[Shurup]

10 cm was just a guess, I think you're right and it's a little too much to do. Might not actually need that much, have to measure that Chinese bike first.

Or maybe I will just get her few of these:

Will be easier and faster and cheaper... just need to figure out how to stick one underneath the shifter...

[Shurup]

OK the Chinese dirt bike is 77 cm high (the seat) but the bike is very narrow so its easier to reach the ground, comparing with the same height seat on a wider bike.

Anyways I think that all it needs to be lowered is 3-4 cm, maybe proper riding boots will take 1 cm away from that...

What do you think folks the best way to lower it 3-4 cm? Will I need to do the from and the rear or only one of them?

[macknife]

Brian at Sumet lowered a CBR250 and can provide the service. Maybe he will notice this thread and give you some advice or send him a PM.

Just from what I know, the front shocks can be lowered on those bikes but you may have to change/alter the 'handlebars'. You can get low profile tires too.

[Jerry Cornelius]

I'm not being contentious,

I've read the post and I just wonder why would you want to lower the bike. It's pretty low already.

Jerry

[KRS1]

- 2 cm from seat foam height

- 2 cm from seat foam width

- 2 cm from suspension sag on softest setting.

- 1 cm from lower triple clamp (will reduce wheelbase)

- 1 cm from wearing boots

- 1 cm @ 30psi tires

- 0.5 cm with full tank of gas

- ??? cm from weight of rider

[Jerry Cornelius]

- 2 cm from seat foam height

- 2 cm from seat foam width

- 2 cm from suspension sag on softest setting.

- 1 cm from lower triple clamp (will reduce wheelbase)

- 1 cm from wearing boots

- 1 cm @ 30psi tires

- 0.5 cm with full tank of gas

- ??? cm from weight of rider

w.r.t. what?

Understand most of what your alluding to, but seat width! How will this affect ride height?

The X factor (rider mass) is the real factor (especially if wearing boots {2 to 4 kg = -1cm} is valid).

Why would one want to sink lower?

On such a light bike, what is gained?

Jerry

[jbrain]

- 2 cm from seat foam height

- 2 cm from seat foam width

- 2 cm from suspension sag on softest setting.

- 1 cm from lower triple clamp (will reduce wheelbase)

- 1 cm from wearing boots

- 1 cm @ 30psi tires

- 0.5 cm with full tank of gas

- ??? cm from weight of rider

w.r.t. what?

Understand most of what your alluding to, but seat width! How will this affect ride height?

The X factor (rider mass) is the real factor (especially if wearing boots {2 to 4 kg = -1cm} is valid).

Why would one want to sink lower?

On such a light bike, what is gained?

Jerry

Because when seat is smaller, the legs are less spread and the feet come lower.

[Jerry Cornelius]

- 2 cm from seat foam height

- 2 cm from seat foam width

- 2 cm from suspension sag on softest setting.

- 1 cm from lower triple clamp (will reduce wheelbase)

- 1 cm from wearing boots

- 1 cm @ 30psi tires

- 0.5 cm with full tank of gas

- ??? cm from weight of rider

w.r.t. what?

Understand most of what your alluding to, but seat width! How will this affect ride height?

The X factor (rider mass) is the real factor (especially if wearing boots {2 to 4 kg = -1cm} is valid).

Why would one want to sink lower?

On such a light bike, what is gained?

Jerry

Because when seat is smaller, the legs are less spread and the feet come lower.

But the mass applied to the suspension is equal. Yes?

[Phatcharanan]

I'm not being contentious,

I've read the post and I just wonder why would you want to lower the bike. It's pretty low already.

Jerry

You must have missed reading post #3 then.

Edited August 2, 2013 by Phatcharanan

[BSJ]

Aside from the lowering which can be done, how about changing the shifter to a push button setup.

All you need are 3 solenoids, some brackets and 2 momentary switches.....and some electrical wiring.

Vola! Push button gear changes.

[Shurup]

^^^ do you mean in conjunction with the platform shoes? I showed her the shoes and she slapped me, I don't think she likes them, nor me making jokes about her height. LOL

Sent from my GT-I9100 using Thaivisa Connect Thailand mobile app

[KRS1]

- 2 cm from seat foam height

- 2 cm from seat foam width

- 2 cm from suspension sag on softest setting.

- 1 cm from lower triple clamp (will reduce wheelbase)

- 1 cm from wearing boots

- 1 cm @ 30psi tires

- 0.5 cm with full tank of gas

- ??? cm from weight of rider

w.r.t. what?

Understand most of what your alluding to, but seat width! How will this affect ride height?

The X factor (rider mass) is the real factor (especially if wearing boots {2 to 4 kg = -1cm} is valid).

Why would one want to sink lower?

On such a light bike, what is gained?

Jerry

lower center of gravity.

any modifications that do with seat height will always change handling characteristics.

seat width is as jbrain stated, and should also be reduced when cutting the height to try and keep similar leverage on the hips as the original seat.

[jbrain]

I had a friend in my homecountry who had a Yamaha Roadliner 1900 and had an aftermarket hydraulic suspension installed, which would lower the bike with just a push on the button.

It even could be operated by remote control, however he soon found out that it wasn't a good idea to keep the remote in his front pocket while riding the bike