Mezzo D9 gearing question

[morphix]

Hi all,

As some of you may know, I'm in the process of planning the conversion of my Mezzo D9 16" folder with the help of Catsnapper.

The Mezzo has 9 speed gears which for me offer the perfect gear range.. I was hoping that I could retain the existing gears have the wheel re-spoked, but Catsnapper tells me this is not possible with the Q100 motor I'm planning to use.

He thinks I can have 7 or 8 speed gears, but that the highest would be 13T giving a low gearing compared to how the gears are now.

The spec of the Mezzo gives the gearing as:

GEAR INCHES
> Gear Ratios for 54 x 12-26 are:
> 11t: 78.9 17t: 51.0
> 12t: 72.3 19t: 44.0
> 13t: 66.8 21t: 41.3
> 15t: 57.9 23t: 37.7
> 26t: 33.4

> Gear Shifter: SRAM Attack
> Chain: 9 Speed HG53
> Chain/Crankset: Truvativ Isoflow 52 tooth with chainguard 175mm
> Cassette: SRAM PG950 11- 26

I'm not very clued up on the gearing side of things, so thought I'd seek some advice on what to do..

Let's see if I understand this correctly... 11T is the highest gear (gear 9) right? So if changing the gears gives me a maximum of 13T, that would be like riding in 7th gear?

I know what riding in gear 7 is like on this bike unpowered and I feel I won't be able to keep up with the motor and will need it more highly geared..

What are my options?

 

[flecc]

That's right. Changing the chainwheel to a larger one is an option to achieve higher overall gearing on a small wheel bike, I've done that to an extreme on mine with a 60 tooth chainwheel:

 

[morphix]

That's right. Changing the chainwheel to a larger one is an option to achieve higher overall gearing on a small wheel bike, I've done that to an extreme on mine with a 60 tooth chainwheel:

Woah. That explains why my 26" MTB is so highly geared I think..because it was originally 21-speed with 3 chainwheels...I removed the left hand (forward) shift and front derailleur and slipped the chain onto the largest chainwheel and smallest freewheel at the back. Now the 1-7 gear shift no longer works and (it's effectively a single gear bike) and it's impossible to ride from a standing start unpowered, but goes like a rocket on full motor power and it's the only way I can keep up

So I guess, I should have 8spd freewheel and then see how it feels with my 52T chainwheel and if I need to move to a larger chainwheel that could help? Is there any benefit or draw back to having 6-spd or 7-spd? I guess that would just make it even more under-geared with no benefit?

With my Mezzo I want to keep the best of both worlds...so I can ride it very highly geared with the motor at full power..but also have a normal gear range to ride it unpowered... I guess that's asking for too much! There's going to have to be a compromise?

 

[morphix]

I thought I'd mention here for anyone interested in converting a Mezzo, the general consensus from people I've consulted seems to be that a front wheel conversion is not possible on this bike, not unless you never want to fold it! And even then, Catsnapper thinks it will require torque arms because of the thin aluminium fork and spacing.

I'm really torn over this one...because the bike feels so good to ride unpowered, the gears feel so perfect! It's just a joy to ride and one of those bikes which feels so natural and comfortable to ride. It seems a crime to convert it almost! I'm wondering if I'm doing the right thing and whether perhaps I should keep this unpowered..and just convert the Dahon instead. Saying that, the Mezzo is the bike I would take further a field with its super compact fold.. so I guess it makes sense for it to be electric. I suppose at the end of the day, if I keep the original wheel and gear cassette all intact, if I decide it's not to my liking powered, I can just convert back...

 

[flecc]

So I guess, I should have 8spd freewheel and then see how it feels with my 52T chainwheel and if I need to move to a larger chainwheel that could help? Is there any benefit or draw back to having 6-spd or 7-spd? I guess that would just make it even more under-geared with no benefit?

That woulds be best, try the 8spd freewheel with the 52 tooth and upsize the chainwheel if necessary. Using a 6 or 7 speed freewheel doesn't necessarily mean less gear range, some are wide ratio, some narrow. For example Shimano make some narrow ratio freewheels where the sprockets just increase a tooth at a time.

In contrast, another solution is to use a megarange freewheel, one very large low gear sprocket for extreme hills or no-power get you home situations, with the rest of the sprockets quite close ratio. I use that solution with a 13 to 34 tooth six speed freewheel with that big chainwheel. It has five sprockets from 13 tooth to 24 tooth, then that big jump to 34 tooth for the very low gear.

For normal cycling wide gear gaps are bad since they upset cycling rhythm, but on a fairly powerful e-bike that hardly matters since the added motor power bridges the gaps with it's help.

 

[catsnapper]

I thought I'd mention here for anyone interested in converting a Mezzo, the general consensus from people I've consulted seems to be that a front wheel conversion is not possible on this bike, not unless you never want to fold it! And even then, Catsnapper thinks it will require torque arms because of the thin aluminium fork and spacing.

Just to clarify the potential problem with the fork. It has a horizontal dropout with a very narrow lower section. The additional load of a motor, plus the extra stress from the required high torque of the wheelnuts,could place an additional stress on the 6061 aluminium forks that in the event of a failure, the torque arm may not be as effective as with a normal fork design.

Alan

 

[Deleted member 4366]

All these things are simple in words, but not so simple in practice. First thing that you haven't told us yet is the width between the rear drop-outs, which may be what decides your gearing. My Dahon was about 130mm, and the frame was very stiff, so I could only squeeze in a 7spd free-wheel. Whatever number of cogs you can fit, you need a 11T top gear likeyou already have, and then you don't have to change anything on the front. You can get 11T free-wheels from Cyclezee for about £25. Please measure the drop-out widths as it's useful information for others, and could be a deciding factor as to whether you can electrify with a hub-motor.

 

[morphix]

All these things are simple in words, but not so simple in practice. First thing that you haven't told us yet is the width between the rear drop-outs, which may be what decides your gearing. My Dahon was about 130mm, and the frame was very stiff, so I could only squeeze in a 7spd free-wheel. Whatever number of cogs you can fit, you need a 11T top gear likeyou already have, and then you don't have to change anything on the front. You can get 11T free-wheels from Cyclezee for about £25. Please measure the drop-out widths as it's useful information for others, and could be a deciding factor as to whether you can electrify with a hub-motor.

The bike has a 9-speed cassette and no problem with the spacing.. I measured it on my first thread about this conversion and it looked to me to be 140mm... Cwah claimed it was 135mm though..

 

[alfie]

I would leave the Mezzo alone and convert the Dahon. Use a nice off the shelf conversion kit and follow d8vehs build. Make thing easy for yourself

I have been riding the Tern for about a couple of months now. The new 8fun motor is very quiet and the kit now has split magnetic wheel like on the Daahub. Had to swap out the BB that negated this a bit though!

Converting a Tern D8 to electric | Tern Folding Bicycles and Folding Bike Accessories | Worldwide

 

[morphix]

I've just took my first night ride on the Mezzo! I had a package to post and being able to scoop up the Mezzo in one hand and get down the stairs without busting a gut makes a refreshing change

I was ok riding on the flat it was very fast and nippy, I was enjoying so much I decided to go a ride around the block...I forgot my limitations and decided to try pedalling up a slight hill which nearly killed me, even in second gear! My knee is suffering now, aching like crazy. I think I would benefit from electrifying it as I have no idea when, or even if, my knee is going to get well enough to pedal up hills without power.

In contrast to unfolding the bike when I got downstairs (which took all of 10 seconds), folding it down when I got back was a nightmare and I struggled for a good 20 minutes with it I need to watch the video again and learn the correct order..I got everything back to front and made a right pigs ear of it again. There's quite a few things you have to remember, like putting the chain in the middle gear, making sure the pedals are turned to the right position clear of the wheels, and not putting the seat stem down until last.. if you forget any of these, the fold doesn't work properly. Also the QR on the front wheel has some technique you need to get used to else it can be quite frustrating getting the wheel out to fold under.. once it's all done though, it makes a pretty neat cube-like fold and wheels along nicely by the saddle.. I'm going to keep practising it until I master it and then I will do a video showing how to do it and some pitfalls to avoid.. I think the video made by Mezzo is not very clear.

 

[morphix]

I would leave the Mezzo alone and convert the Dahon. Use a nice off the shelf conversion kit and follow d8vehs build. Make thing easy for yourself

I have been riding the Tern for about a couple of months now. The new 8fun motor is very quiet and the kit now has split magnetic wheel like on the Daahub. Had to swap out the BB that negated this a bit though!

Converting a Tern D8 to electric | Tern Folding Bicycles and Folding Bike Accessories | Worldwide

Good article alfie! Maybe I'll do something similar for Mezzo owners.

Btw, I think the white frame bike with the black seat post and handlebar stem/handlebar looks very cool and modern.. I really wanted a bike like that initially.

 

[morphix]

Alright, hands up, who owned one of these? I owned one of these as a kid (that's the American version pictured) and it was the most comfortable bike I've ever owned with the easiest gear shift..1-2-3 Sturmey Archer hub gears! If only bikes were built like that today =)

 

[morphix]

I think I found an ideal compact and smaller derailleur for the Mezzo:

The Shimano Tourney FT30 Short Cage Rear Derailleur - Direct Mount is 6-or 7-speed rear derailleur compatible with an 11-tooth sprocket and offers SIS rear shifting. Using the smallest cage in the Shimano range this derailleur is suitable for folding bikes or wheel sizes from 16 inch (compatible with single chainring only). A wheel type cable guide provides super light shifting action.


Compatibility:Compatible with an 11 tooth sprocketNotes:Compatible with a single chainring only

Shimano Tourney FT30 Short Cage Rear Derailleur with Hanger Bracket - 6/7-Speed - £15.29 from Evans Cycles - free delivery (14% discount possible, 4% from TopCashBack and 10% with voucher code EX10CPA