Change bike's front chainring to increase top speed?

[FlatSix911]

Is there an universal standard about how many torque applied on each bolt of the chain ring? or it is brand specified?

What is the torque needed for chainring bolts?

I have a bike that is no longer in production, but it has a standard drivetrain (FSA). I had some shifting issues the past couple days, and to my surprise when I did a clean/inspect, three of the 5

bicycles.stackexchange.com

Unfortunately, there is no universal standard... the torque depends on many factors: OEM, Steel or Aluminum, etc.

A Shimano "General Operations" manual states the tightening torque for road chainwheels is 12-14 N-m.
For mountain bike chainwheels it's upped to 14-16 N-m for large and middle ring and 16-17 N-m for the smallest ring of a triple.
The website: http://si.shimano.com/#/

 

[Karm]

What is the torque needed for chainring bolts?

I have a bike that is no longer in production, but it has a standard drivetrain (FSA). I had some shifting issues the past couple days, and to my surprise when I did a clean/inspect, three of the 5

bicycles.stackexchange.com

Unfortunately, there is no universal standard... the torque depends on many factors: OEM, Steel or Aluminum, etc.

A Shimano "General Operations" manual states the tightening torque for road chainwheels is 12-14 N-m.
For mountain bike chainwheels it's upped to 14-16 N-m for large and middle ring and 16-17 N-m for the smallest ring of a triple.
The website: http://si.shimano.com/#/

The Fouriers dealers told me to use 4-5N.m for the Fouriers 40T chainring. I don't know if it's that small torque. They told me the chainring is more hardened than the previous 40T I've found. But they also told me to use a new chain because it needed additional length of a chain? What? After so much hassle, to get a new measured chain, the empty padel happens again like an old beach. Then they told me my cassette is done. Wasted a whole day. What a bicycle experience. Then I swap old chain, it padels fine. So much for the bicycle components.

 

[E-Wheels]

Torque Specifications | BikeRide

www.bikeride.com

 

[FlatSix911]

Torque Specifications | BikeRide

www.bikeride.com

Great resource... thanks for sharing!

Bicycle Torque Specifications​

The following table lists general torque specifications for common brands and components. Contact the manufacturer for updated torque specifications. We will keep this chart updated so if you want to add information or notice any errors please let us know.

Categories​

• Bottom Brackets
• Brakes
• Brakes (Disc)
• Cassettes & Freewheels
• Chainrings
• Cranksets
• Derailleurs
• Levers (Brakes)
• Levers (Shifter)
• Handlebars
• Headsets
• Pedals
• Seats & Seatposts
• Stems
• Wheels & Hubs

 

[Karm]

Torque Specifications | BikeRide

www.bikeride.com

If you can find the Fouriers

 

[percymon]

There is no mention on Fouriers of the tightening torques for any of their chain rings,, at least not in their parts catalogues - perhaps an email to their technical personnel ?

Other than needing a longer chain to account for the larger chain ring, i can't see that causing any further issues for you ? You may have enough length in the old chain but i'd expect the deraileur carriage to be pulled forwards somewhat in that case

Perhaps you need a better dealer ?

 

[Karm]

There is no mention on Fouriers of the tightening torques for any of their chain rings,, at least not in their parts catalogues - perhaps an email to their technical personnel ?

Other than needing a longer chain to account for the larger chain ring, i can't see that causing any further issues for you ? You may have enough length in the old chain but i'd expect the deraileur carriage to be pulled forwards somewhat in that case

Perhaps you need a better dealer ?

I don't know since when dealers are different from each other. Because there is no standard? And I don't usually need a dealer except into some snakeoil market or luxury food market that has no standard at all. Anyway, the bike is bought like yesterday, and today the Japanese Shimano cassette is done. Worn out, skippy. They said my KMC chain is too strong for the factory cassette. I really don't enjoy wasting 2 hours fixing a bike that only let me go 50 miles in 2 hours. Usually in 2 hours I've already reach 200 miles mileage on a true vehicle instead dealing components crap like this.

 

[Karm]

So after all the snake oil troubles with a simple request of boosting speed, the 40T chainring is installed and works without killing other components. It turns out the bike is still restricted at 43km/h even I have done the 25km/h button combo derestrict, no more motor boost after this speed. Is this a joke?

 

[FlatSix911]

So after all the snake oil troubles with a simple request of boosting speed, the 40T chainring is installed and works without killing other components.
It turns out the bike is still restricted at 43km/h even I have done the 25km/h button combo derestrict, no more motor boost after this speed. Is this a joke?

I thought you said your bike was de-restricted in your original post? Perhaps is still limited to 45kph / 28mph.

 

[Karm]

I thought you said your bike was de-restricted in your original post? Perhaps is still limited to 45kph / 28mph.

No, de-restricted. Or it's 25km/h, but now it's 43km/h, not your 45km/h. This is some your BS double turtle restrictions?

 

[Stefan Mikes]

What is this derestrictor, precisely?

 

[Karm]

What is this derestrictor, precisely?

Default built-in derestrictor. Nothing hotwired. Just button combo derestriction applied.

 

[Stefan Mikes]

I was asking because there is VolSpeed V2 in my Giant e-bike that can delimit the speed up to 99 km/h. Actually, it is doable to achieve 57 km/h on the flat with 36T chainring on this e-bike.

 

[FlatSix911]

No, de-restricted. Or it's 25km/h, but now it's 43km/h, not your 45km/h. This is some your BS double turtle restrictions?

You seem a bit confused as to what speed limit you actually have... check again and report back.

 

[Karm]

I was asking because there is VolSpeed V2 in my Giant e-bike that can delimit the speed up to 99 km/h. Actually, it is doable to achieve 57 km/h on the flat with 36T chainring on this e-bike.

There is none in the bicycle and it's in fact derestricted, or it's 25km/h, but it has double speed limit. So you have to get into another level. Nothing hot wired, and I don't want to buy another snake oil to derestrict the junk.

 

[percymon]

Perhaps there is some other secondary protection system in place?

Theoretically the motor assists up to 120rpm which on 27.5 x 2.4 tyres and 40x11 gearing gives a theoretical 58km/h speed. This tyre combo was offered by giant as alternative to 29 X 2.25” for increased stability (at expense of speed). There are lower resistance tyres than the Aspen of course.

Are you definitely running out of motor assist at your 43km/h speed or just maxed out with air resistance, tyre resistance etc ?

mare your motor tuning options turned down in the app ?

 

[Karm]

Perhaps there is some other secondary protection system in place?

Theoretically the motor assists up to 120rpm which on 27.5 x 2.4 tyres and 40x11 gearing gives a theoretical 58km/h speed. This tyre combo was offered by giant as alternative to 29 X 2.25” for increased stability (at expense of speed). There are lower resistance tyres than the Aspen of course.

Are you definitely running out of motor assist at your 43km/h speed or just maxed out with air resistance, tyre resistance etc ?

mare your motor tuning options turned down in the app ?

Definitely double restriction. It should go beyond 50km/h easily. But the motor stops powering beyond 43km/h. When I was downhill I can easily tell from the evo display that the power assistant bar is no longer active after 43km/h.

 

[percymon]

It sounds like you are hitting the 28mph maximum assistance for Class 3 e-bikes

 

[Lord Zene]

I have a Giant MY19 XTC E+ Pro with MY19 Syncdrive Pro motor. The bike is derestricted and It's equipped with 27.5' Maxxis Aspen tires and DT Swiss EX 1501 wheel sets. But the top speed is only at 43 km/h.
I can hardly go faster like the motor's 120 rpm is at its max. And a 240W 80 N.m motor should be enough to push over 43 km/h.
So I am thinking if it is possible to change gears from the original 36T chainring to a 38T or a 40T and increase the top speed. I have a TB-1069 Ebike lockring tool to get off the chainring.
View attachment 68906
Anyone has done this before?

You can go up to 52 t through bafang if I’m not mistaken. That’s the easiest thing to do and it will use that torque. This has to be old. But we did this in the 80’s kn leg powers when racing bmx. If you were strong enough anyway. Can take your smallest in the back and make it smaller too. Cheapest top speed you can find. And effective.

 

[Hasaf]

I ended up changing both the chainring and the rear cog on my NuVinci N380 equipped bike using a TSDZ02 Motor. Before I changed them the gearing was just wrong and the bike topped out around 15mph. Now, with no wind, and given long enough to get there, it tops out about 22-24mph.