New Crankset on Dahon Mariner 7 speed - Do I need to change the bottom bracket?

[Dahonathan]

Hi there!

I just purchased a Dahon Mariner 7 speed - I am not sure what year it is but it is in almost new condition. Pic Attached.

I'd like to swap out the crankset to something a bit lighter and (frankly!) looks better - the stock crank/chainring looks a bit cheap to me!

I think the stock chainring is 52 teeth, but I am interested in getting this Litepro crankset which has 53 teeth:

Litepro Crankset 53th

It says that it is compatible with folding bikes and Dahon, but I don't know much about bikes at all, and having googled around I can't seem to find any information on compatibility. I know my bike has a square crank thingy, as does the Liteproe, but does anyone know if it is a simple case of taking my chainset/cranks off and swapping them for the litepro, or might I also need to swap out the bottom bracket?

Also, is there anything to consider regarding this Litepro crankset and my Dahon being a 7 speed? I'm not sure if certain chain rings are made specifically for 7/8/9 speed gearing etc, or if the extra tooth on the Litepro chain ring will affect anything? There is little to no slack in my current chain, so I assume I'll need a new chain UNLESS the actual teeth are smaller.....I just do not know.

Any help would be appreciated.

Here are a couple of pictures, one of the bike and one of the existing crank set.

Thanks!

 

[tds101]

No, you don't need to change the bottom bracket if you change the crank arm/sprocket. I own multiple folders, including the Mariner i7, and they all have a standard square taper bottom bracket. The issue some have on a derailleur based folder is the chainline when only the chainring was changed. You should be good with this mod. My Origami Wasp has the Neco crankset and Litepro 58t 130 bcd chainring on, and it's excellent. I also have since swapped the pedals for aluminum Wellgo 265 folders, and some cheap mudguards I purchased off of Amazon USA.

PS: 2 pics of the Mariner i7 below added.

 

[Dahonathan]

No, you don't need to change the bottom bracket if you change the crank arm/sprocket. I own multiple folders, including the Mariner i7, and they all have a standard square taper bottom bracket. The issue some have on a derailleur based folder is the chainline when only the chainring was changed. You should be good with this mod. My Origami Wasp has the Neco crankset and Litepro 58t 130 bcd chainring on, and it's excellent. I also have since swapped the pedals for aluminum Wellgo 265 folders, and some cheap mudguards I purchased off of Amazon USA.

PS: 2 pics of the Mariner i7 below added.

View attachment 644422

View attachment 644425

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Thanks for your reply! This is good to know I think the factory fitted crank and chainring is a single unit - I can't swap out the chain ring, so hopefully that new Litepro crankset will align ok with the derailleur.

Out of curiosity, what affect does putting a larger chain ring on have? You say you put a Litepro 58t chainring on your Wasp (nice bike!) - does a larger ring make the gearing harder to peddle or easier? I will mostly use the Mariner for casual riding around here in Amsterdam so it doesn't have to be a speed demon, but when I was out on the open road for the first ride I did find that 7th gear wasn't quite enough "Oomph" when I got up to speed. I had to stop peddling and just cruise.

 

[tds101]

Thanks for your reply! This is good to know I think the factory fitted crank and chainring is a single unit - I can't swap out the chain ring, so hopefully that new Litepro crankset will align ok with the derailleur.

Out of curiosity, what affect does putting a larger chain ring on have? You say you put a Litepro 58t chainring on your Wasp (nice bike!) - does a larger ring make the gearing harder to peddle or easier? I will mostly use the Mariner for casual riding around here in Amsterdam so it doesn't have to be a speed demon, but when I was out on the open road for the first ride I did find that 7th gear wasn't quite enough "Oomph" when I got up to speed. I had to stop peddling and just cruise.

The crank arms and chainring are definitely one piece, so the only way to upgrade is via the complete swap that you're doing. Definitely a nice upgrade. It should line up nicely (pics afterwards please!).

A larger chainring + smaller rear sprocket = more speed. This little thing is decently fast for an inexpensive little ride (gear inches are about 35-89). I got the bike on sale for $199 USD, and with everything, if I remember correctly, it's under $300 USD for all the mods. I'd eventually like to change out the brakes, as they're a bit too mushy. Otherwise, not a bad little ride.

 

[Kell]

Having more teeth on the chainring will make it harder to pedal across all of your current gears. With one extra tooth, the difference won't be massive, but it will be noticeable. I recently swapped out my 50T Brompton chainring for a non-oem 48T one and can definitely tell the difference.

The only question to ask is if your current 1st gear will still be low enough to copy with any inclines?

The advantage of moving to something with replaceable chainrings is that if you decide you still need more top-end speed you can buy a chainring with more teeth. Just use the BCD printed on the chainguard as your reference - i.e. 130BCD

 

[tds101]

I do wish the low gear was a bit lower for hills, as 35 gear inches isn't the best. Where I am is mostly flat, so it's not too bad.

 

[tds101]

Slightly newer pic of the Wasp,...