pedals no resistance once up to speed

[Atlav4]

erm right brand new to all this but here goes out riding round the estate pas working great can really feel the motor assisting making the peddling a breeze but then out on the road straight onto an incline bike in 6th gear (10 in total) motor pulling great crested the hill dropped into 8th gear thinking here we go BUT resistance in pedals gave out (just spinning)? coasted for awhile lost speed then resistance with aid from motor came back feeling like when your in to low a gear like i said first time on a push bike never mind an pedelec this happened at about 15mph (no speedometer) anybody is this normal am i doing anything wrong cheers

 

[Fat Rat]

Hi
Pedelecs cut assistance in and around 15.5 mph
This is probably what your feeling

 

[Atlav4]

Thanks m8 and hi yes I understand that at about this speed the motor stopped assistance but but I thought you could pedal on your legs like a normal bike are the small cogs 10th gear and the largest 1st gear or is the other way round sorry never even road a bike with gears sshheesshh talk about a greenhorn lol

 

[soundwave]

you ran out of gearing and thus span out so could add no more power.

what size front sprocket does it have and what bike is it?

 

[Fat Rat]

Thanks m8 and hi yes I understand that at about this speed the motor stopped assistance but but I thought you could pedal on your legs like a normal bike are the small cogs 10th gear and the largest 1st gear or is the other way round sorry never even road a bike with gears sshheesshh talk about a greenhorn lol

Yes the large cog is 1st and the small cog is top gear (rear)

 

[Atlav4]

Hi the bike is a Gtech escent so I was in 8th and should have felt resistance at that speed sorry don’t know size of front cog

 

[Benjahmin]

Can't find the spec for this bike but, from the pictures, the front chain ring looks quite small. If so, this means it is geared more to being a mountain bike than a road bike - it's sort of inbetween.
So this means that going down hill - on a road- in 8th gear the speed of the bike will soon be going faster than your legs can keep up with. They spin so fast that the feel is of no weight, as you say.
My bike has a 48 tooth front ring and the smallest cog on the back is 12. I 'spin out' at around 30mph with this gearing. My guess is that you are spinning out at around 20mph. If you count the number of teeth on your front cog, then the number of teeth on the largest and the smallest of the rear cogs, we can advise more.
The easiest fix is to change the frong cog for a larger one , 46-48 teeth is usual for a hybrid, up to 54 for a race road bike.

The basic priciple is:
The bigger the size difference between front and rear cogs, the greater the mechanical advantage, so the faster the machine can be driven at.
The less the size difference the easier it is to drive the machine up hill.

 

[Atlav4]

thankyou for a great reply front cog is 36t not sure of back one been out today on road and old track think i understand the principle of larger front cog greater speed never been on a bike for so long top speed in 10th gear seemed to slow to reach limit but on the dirt track keeping the mountain bike just on speed of traction seemed quite fast enough (dodging puddles and potholes etc) quite a fit 58yearold so would the bike be even better with a larger front cog and how hard would it be to do this thanks again for the explanation

 

[Benjahmin]

Yeh, 36t is in mountain bike territory.
Not sure what they put on G-techs, it may not be a generic part. We'll need to see some photo's of the crank/bottom bracket area to be able to help.
Upping the front ring into 44-46 area should give you decent road speed whilst still allowing you to get up hills.

 

[Atlav4]

book says gears are 10 speed 11-36 teeth cassette ? is it just a case of fitting a larger chainring probably upset mtb owners but as its geared 1st 2nd and 3rd gears seem to almost redundant literally fly round when hardly moving at all but can see they might be needed on severe slopes etc

 

[soundwave]

that is 10-50t rear and 50t upfront as the smaller front sprocket has a 2.5 ratio and can go 30mph on the flat with effort

 

[Benjahmin]

With 11-36 on the rear a 46 or 48tooth front would give you decent road speeds on top gear (10th) whilst still allowing you to climb just about anything you'll come across on roads (1st - so long as you have the legs/effort available).
At 48t you would probably find that 9&10 don't get much use, just on downhills when you're full of the joys of spring !
46t may be the place for you. My missus (also not a life long cyclist) had this on her Dutch style bike and it seemed to suit her.
Ignore Soundwaves post. His bike is a mid drive and the gearing is totally different issue. It's just that he's a speed junkie bless him.

 

[Atlav4]

Hi m8 cheers for the info is it just a case of buying a 46t cog as long as the bolts fit and changing it over and will the chain be okay thanks

 

[soundwave]

yes you just need a bigger front sprocket id say 46 is about right tho id not go much bigger.

 

[Atlav4]

Thanks speed freak I think I’ll look to attempting changing especially as won’t have any other issues thanks for that m8

 

[Benjahmin]

Need to see photo's of crank and bottom bracket area. Not all are the same.
Chain should be fine but there may be some adjustment of the deraileur needed.

 

[Atlav4]

Hi m8 away till Saturday but will take the pics you need and maybe you can help with advice thanks dude will post back then thanks

 

[Atlav4]

hi sorry about the delay in replying heres some pics hope they help cheers am beginning to think might only need a 42t or 44t on the front as the top speed i think i need to achieve is above the pedelecs assistance (longer battery range) but not hair raising speed i know i need a hell of a lot of riding time to really make these assumptions but at present the spin out speed is too close to assistance cut out speed hope this makes sense thanks

 

[Benjahmin]

Hi Atlav,
Looks like it's a satndard square taper. If so, the hex head insert will screw out, and you should see then end of a square shaft. Here's a link to a video showing how to remove the cranks.

You can get a crank puller from Halfords for about £13 or here's one for £5.

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You will need to buy a chain ring complete with a pair of cranks - I know seems a waste but your ring is attached to the crank arm.
Despite what you say about top speed, I would still say go for a 46t crank set. It will give you a nice easy road riding gear range.
With luck the chain should be OK, However the first time you go onto the bigger rear cogs, go one at a time and check the deraileur arm isn't getting pulled too far back.
This is man shed bike maintenance - love it!

 

[Atlav4]

thanks once again m8 for your reply need more ride time (weather please) but take on board your suggestion ask the son in law to have a look at doing the adjustments hes the mechanic intend to post on the effects of the changes once done cheers