Chain ring help

Hi all. Does anyone know what the largest chain ring I can fit to my carrera e vengeance 8sp please. Currently have 40t.Thanks

I have a Carrera Crossfire, it's got a 48t fitted.

Hi. Thanks so would that fit on mine.?

As you have no front derailleur to worry about it shouldn't pose much of an issue, you will need to check that a larger chain ring has clearance and won't hit scrape against the rear chain stay. You will need to add extra chain links if going from 40 - 48t other wise the rear derailleur will likely be to taught and affect gear changes.

 

You will lose lower gearing and gain higher gearing, even with a Bafang hub inclines/hills will be a little slower/harder to climb with loss of the lower gearing as you will be grinding the speed out rather then spinning as freely with a lower tooth chain ring.

 

48t is more suitable for on the road riding but for off road/trails or forest the 40t or lower will be better suited.

Edited July 15, 20196 yr by Nealh

That's great. Thanks alot

If you do change it check the chain length by removing it from the derailleur and placing said chain around the front chain ring and the largest gear/#1 on the cassette. The chain ends should overlap by two complete links for correct length, likely that you will need to add links rather then remove any or count the total links in your chain and simply buy a longer chain with the correct number of links if need be.

OK thanks. Just to check it will make a real difference to the gearing if I go to 48t.the result I'm after is much higher gears in 6/7 and 8th gear. I never use 1-5.

You will with a 48t!

Thanks all

How old/strong are you?

 

I'm pretty strong but I can't pull 48:11 anymore (young had a 52 tooth). At cadence, downhill, I can manage 48:15 or if it is really, really steep 48:13, my cadence drops to 60 or below if I try 48:11.

 

Now if I add a hub motor to the mix I can pedal all day at 48:17 = about 34 km/h at cadence (95 rpm).

 

Chainwheels don't cost the earth, buy a 44 or a 46 as well in case the 48 is too great an increase.

My legs are really strong but the rest of me is 54 years old. OK I'm might try a 46t first. I've just put road tyres(Schwalbe big Ben's) on to replace the kenda nobblies and I can't believe how much faster I can go. Hence the need for higher gears. I mostly ride flat roads and never go on the dirt. Thanks

46:11 @ 90 rpm is 48 km/h with Big Bens, on a really steep downhill you would probably spin out at over 60 km/h.

 

All numbers with a 26" wheel.

OK. I free wheeled down a big hill today and speedo read 36mph.good fun but bit scary. It rolls so much better with the big Ben's. I didn't realise how much frictional drag you get with nobblies.

You should try slicks

 

I beat you, 67 km/h on my first pedelec. Haven't measured the speed of the trike yet but so close to the ground it feels even faster...

The Crossfire is 700c wheels. I find Cadence starts to get too fast around 32mph (down hill - I'm old!), that's with a 12t top gear. I use it a lot on gentle down slopes when lower cadence is OK.