Change from ScrewOn Freewheel MFTZ06 shimano question

kennyk

Hello, I have a cheap made in china MTB, it's got 6 speed on rear, Shimano Mf-tz06.
Teeth ratio : 14,16,18,21,24,28. (Screw on Freewheel, Shimano 6 Speed index spacing).
I want to swap this with something with low teeth ratio, like 11, then whatever upward.
Can anybody recommend me specific cassette model to replace to please?
I'm quite a newbie and don't even know if it has to be shimano or if any brand is OK or not.
Will 7 speed cassette be possible for replacement?
As long as I can achieve riding on 11 teeth, I don't mind not using 1 gear.
All I want to achieve is to swap my current cassette with something that let me ride faster (lower teeth).
Sorry with newbie question.

Please help.

cooldad

You can't replace a screw on freewheel with a cassette, without changing the wheel.

And I've never seen a freewheel with 11 teeth.

kennyk

Thank you for reply.

How about freewheel with 12 or 13 teeth? does it exist?
How much difference does it really make if I went from 14 teeth to 13 teeth?
I want to go super fast with this shitty bike to make roadracers feel like sh!t

The Rookie

You could get them with a smaller number but once they were only used on beater bikes the stopped making them, hence why I suggested a bigger chainwheel at the front instead for the same effect.

So what size chainwheel do you currently have?

Gearing doesn't make you faster, power does, a BSO mountain bike will need circa 50% more power than a decent road bike for the same speed due to the increased drag and mechanical losses.

BigAl

cooldad wrote:

You can't replace a screw on freewheel with a cassette, without changing the hub

FTFY

kennyk

Unfortunately it's not an option to change chainwheel because I cut all the wiring and took the shifter off for chainwheel already. The bike used to have 18 gears (3 front, 6 rear) but now it's got 6. I'm not willing to put on a new shifter and rewire for the chainwheel for this cheap bike at this moment. I think this is more difficult work for me than modifying rear wheel/gear.

From all of your inputs, it seems changing the hub on the rear wheel is the only way to go for me? What exactly do I look for? I've posted another question asking about tire size, I want to go narrower because I think that would help the bike go faster. Considering the change of tire and gears, is it cheaper to buy entirely new wheel which comes with gears with 11 teeth? and with narrower width? any useful ideas are appreciated.

Thanks

kennyk

Actually, I don't need to be concerned about the shifter to the chanwheel.. all I need to do is just replace the largest chainring to an even larger one (with more teeth), as the Rookie suggested. This probably is the easiest and the cheapest solution. Am I correct? If I change to much larger chainring, might I need to replace chain to longer one as well? Anything else to watch out for relating to chainring replacement?

The Rookie

Yes you just need a new larger chainwheel (which may mean new cranks if yours aren't removable) and is the easiest and quickest solution.

You should need a new chain unless your current one is already too long already (not unusual), as a rule of thumb you need to add half the number of links as the extra number of teeth on the chainwheel.

kennyk

I've looked around on internet for 50+ teeth 4 bolt chainring, but apparently it's not easy to find one. Most of 50+ chainrings are 5 bolts. Could anybody point me to a good webshop in Europe (including brexited UK ) where I could find what I look for? I don't want to change the entire crankset for this bike. If I can't find one, maybe changing the rear gear is a cheaper option than to replace crankset?

The Rookie

Two options, fit a 48 which is available in 4 arm, or if you have to replace the cranks anyway (yours are probably riveted so you can't change a chainwheel) just get some road cranks.

kennyk

I've found potential replacement to MFTZ06, that's "DNP Epoch Freewheel: 7 Speed 11-28T ".
It's less than 30 pounds on ebay uk, I think this is a better solution.
If anybody knows DNP is good or not, please let me know.
Plus, my bike already has 48t chainring, I wanted to go 50+ initially.
Thanks for the reply tho!

The Rookie

No idea of the quality, but should do what you need.

kennyk

After extensive research, I decided to buy the DNP 11-28 Freewheel. Will update how it goes after it arrives and is installed.