Can ride one bike but not other... any ideas

[Pete270]

Hi there,

I am new to this forum. I have been learning to ride I have mild cerebral palsy and I have managed to ride a bike. (See the picture attached) I bought a bike for balance practice. (Black frame picture) With my new found freedom I have tried to ride this bike but as I push down I can’t bring my left leg up.

Any tips / or idea what the frame is I learnt on is? (White frame)

I don’t know if crank lengths or chain set up or different.

Any advise given I’ll be grateful.

Thanks,

Peter

[Grandad]

Immediate thought is a fixed wheel but an inexperienced rider might find it a bit difficult to get used to. Would also need a different bike so hopefully there will be some better suggestions.

[Eyebrox]

It looks like an X-rated Jump bike from Halfords. 18 speed with three chainrings at front. This bike shouldn't act like it has a fixed wheel ie causing the left crank to turn in line with the right crank turning as you pedal. However some of these bikes might indeed perform this way if the gearing is worn. If this was the case, the right foot would pedal as normal and the momentum from doing so would keep the left side turning. Not sure if that explains it. You would be better with a bike which has a fixed wheel. This would support your left leg as the right leg does almost all the work. Might be tiring though because fixed wheels don't allow the rider to take a break and keep the pedals static during the cycle.

[Brucey]

is there a big difference in the saddle height?

cheers

[eileithyia]

My immediate thoughts are maybe a lower saddle and or shorter cranks so there is less effort / distance to get the pedal up from the low point.. if that makes sense.

The other explanation might be as others have said, the gear might be worn / damaged so instead of freewheeling it is behaving more like a fixed gear. If you can lift the bike so the back wheel is off the ground and you spin the wheel, (get someone to help) do the pedals go around as well? If so that might be your answer.
I wonder if toe straps would help, ie tighten around your left foot so you can pull up as you push down with your right?

[peetee]

I don’t think the black bike would create a freewheel effect. A stuck freewheel would retract the rear gear mechanism before it pulled on the crank. In the meantime there would be a lot of slack in the upper part of the chain. In this sort of a scenario there is a lot of noise, skipping and jumping and the bike may well come to a jarring halt as the chain jams.
I think too that the saddle isn’t high enough and the overall poor condition of the bike is creating too much resistance.

[Chris56]

My first port of call would be looking at the saddle placement. Looking at the picture it might be a bit far forward. By mocing yiu seat fuether back it could make your lower leg a bit more verical on the way back up, making it eaier to raise your knee. Have a look at this link and then see how your knees line up:

https://www.bikeradar.com/advice/fitnes ... ght-right/

Also, great to hear that you are turning to 2 wheels dispite your additional challenges - a warm welcome to the forum!!!

[Pete270]

First of all thank you for all your replies. I have cranked the peddle up on the black bike. But still when I push down with my right foot the left peddle comes up but I can’t get my left food high enough (due to limited hip flex).

Does any one know what style of bike the white frame is that I managed to cycle on. The cracks did seem to the lower on it. (See picture attached)

I bought the black bike to learn balance on so did not spend loads on it (thanks eBay) I am thinking a low step through frame (maybe a women’s bike ) it’s annoying that I can’t try out bikes (due to Covid) I am nervous about buying online. I think I might wait until shops open again. Anyone know a good independent bike shop in Redbridge area I’d rather support local than massive chain.

Thanks,

Peter

[531colin]

Hi Pete, and well done for having a go!
Don't rush into buying another bike! As it happens, you have probably picked the worst time to learn to ride; when we are not struggling with a pandemic, there are organisations up and down the country which help people with various disabilities (etc) to get up on two wheels; just Google "disability cycling your town". They will help you get riding, and give you advice on buying a bike. They can probably put you in touch with a local charity which mends old bikes to sell, or will help you fix up a bike. I Googled "disability cycling Leeds" and there are several in my nearest big town.

For now, I have a few suggestions. I guess you mean you can get up and riding on the white bike, but you can't get started on the black bike?

On the black bike, you have 3 chainrings at the front (where the pedals are). Get the chain on the middle one by turning the pedals and working the gear control for your left hand. ....the back wheel needs to be off the ground, it can be a 2 person job. Similarly, get the chain on a back sprocket somewhere near the middle.....right hand. Try again to get riding now you have got it in a sensible gear.
Try starting off on the black bike using the "other" foot.

When you get the chance, get somebody to video you starting off on the white bike, and trying to start off on the black bike. (I think you need to post a video on you tube and link it here; there are better people to advise than me!)

Its much easier to do this face to face, but we will do our best!

[Brucey]

the cranks of the white bike do look shorter than normal and the bottom bracket height looks lower than normal on that bike too. If you get a chance to measure those things you can make sure that another bike is more like this. However low bottom brackets and short cranks are more often found on children's bikes, and on those bikes the saddle may not go high enough for you.

If you want to convert a bike to make it more suitable for you , you can find shorter cranks fairly easily but getting the bottom bracket lower on an existing bike isn't so easy; one way is to fit a smaller rear wheel, which will work OK with a disc (or hub) brake fitted but not so much with rim brakes.

hth

cheers

[LittleGreyCat]

I assume that the white bike isn't yours.

Perhaps you could post a picture of you sitting on the black bike so that we can see if the saddle height above ground is roughly the same?

For clarity, can you set off and get your left foot on the pedal but then not get your left knee high enough when you push down with your right?
Or are you struggling to get your left foot on the pedal at all?

[Tigerbiten]

How long are the cranks on the black bike ??
If they are 175mm then you'll have to lift your leg higher vs 170mm cranks.
I wonder if it could be something as simple as that.

Luck .......

[andrew_s]

I'd suggest raising the saddle on the black bike.

On the white bike, when on the saddle, both heels are about 4 cm off the ground (assuming it's you in the photos).
That's fairly normal for a new-ish cyclist.

The black bike has a very low saddle - the sort of height you see on a yoof's bike, set up for stunts and mucking about on rather than going somewhere.
Because the saddle is low and the pedals are a similar height, you've got to get your foot closer to your backside than on the white bike.

[Pete270]

Hi all,

Thanks for the replies I have tried raising my saddle using the heel and knee bend. I lowered it so I can scoot the bike home and took the photo (not helpful I know). I will raise the saddle at the weekend and take a another picture.

I have looked into the saddle position and I can’t move it back does not look like it has the adjustments.

The cranks measurement is 19 cm (190mm) I’ll admit even as a cycling novice I think they are massive. I am measuring from the end of the crank (near the nut) to the peddle. I have read cranks should be 10% of your height 5’8 176cm so my cranks should be 17cm ish maybe even shorter to allow for limited flex.

Thank you so much for everyone taking the time to respond.

Thanks,

Peter

[ElCani]

Cranks are measured from the centre of the hole for the axle to the centre of the hole for the pedal, as shown in the image linked to below.

https://images.app.goo.gl/pyvBD9JJwiwfA6QJ9