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-   -   Chain Ring Guard/Chain-wheel Protector (https://www.bikeforums.net/showthread.php?t=1200233)

JackieYan 05-04-20 01:36 AM

Chain Ring Guard/Chain-wheel Protector
 
I hope I can explain myself clearly, as I don’t know all the names of the different parts. I’ve looked the parts up from a drawing, so hope I’m using the correct names.

I’m looking for something to cover the crankset/outer chainring on the front crank.
My problem is when sitting at traffic lights, for example, and I turn the crank to get it in the right position to move off, I sometimes rub the inside of my leg/sock along the chain itself, becoming covered in oil.

I googled, and ebay came up with something called “Bicycle Crankset Cap Bike Chain Wheel Cover Protector”
It looks to me like it screws into the crankset and is a larger diameter than the outer chainring. To my mind I’d hope that would prevent me touching the chainring and chain?

The one I saw said, “This bike chain cover is available as long as your bicycle tooth tray is 42T, 44T, or 46T. To use this cover, you must have screws in the crank hole of your bike”

I have four unthreaded holes in my crankset.
I have a Merida Big Seven 300. I counted the number of teeth on the outside chainring(?) There are 40. The chainring is almost 17cm in diameter (including the teeth)

Or perhaps someone can suggest a better/easier alternative to stay clean?

Ross520 05-04-20 04:25 AM


Originally Posted by JackieYan (Post 21453987)
I hope I can explain myself clearly, as I don’t know all the names of the different parts. I’ve looked the parts up from a drawing, so hope I’m using the correct names.

I’m looking for something to cover the crankset/outer chainring on the front crank.
My problem is when sitting at traffic lights, for example, and I turn the crank to get it in the right position to move off, I sometimes rub the inside of my leg/sock along the chain itself, becoming covered in oil.

I googled, and ebay came up with something called “Bicycle Crankset Cap Bike Chain Wheel Cover Protector”
It looks to me like it screws into the crankset and is a larger diameter than the outer chainring. To my mind I’d hope that would prevent me touching the chainring and chain?

The one I saw said, “This bike chain cover is available as long as your bicycle tooth tray is 42T, 44T, or 46T. To use this cover, you must have screws in the crank hole of your bike”

I have four unthreaded holes in my crankset.
I have a Merida Big Seven 300. I counted the number of teeth on the outside chainring(?) There are 40. The chainring is almost 17cm in diameter (including the teeth)

Or perhaps someone can suggest a better/easier alternative to stay clean?

Why not just be more careful?

Can't say I've ever gotten a chain tattoo rotating my crank.

hillyman 05-04-20 06:11 AM

Might be tough to find one that will fit your particular crankset if even exists or will even work at all. Some cranksets come with a factory one already installed but that's another can of worms if will work with your system. Maybe somebody here more of an expert but I basically agree with Ross520, you will learn easier to keep your leg out of the way than hours trying to find, buy and install a guard that is a coin toss on fitting.

FiftySix 05-04-20 06:48 AM


Originally Posted by JackieYan (Post 21453987)
I hope I can explain myself clearly, as I don’t know all the names of the different parts. I’ve looked the parts up from a drawing, so hope I’m using the correct names.

I’m looking for something to cover the crankset/outer chainring on the front crank.
My problem is when sitting at traffic lights, for example, and I turn the crank to get it in the right position to move off, I sometimes rub the inside of my leg/sock along the chain itself, becoming covered in oil.

I googled, and ebay came up with something called “Bicycle Crankset Cap Bike Chain Wheel Cover Protector”
It looks to me like it screws into the crankset and is a larger diameter than the outer chainring. To my mind I’d hope that would prevent me touching the chainring and chain?

The one I saw said, “This bike chain cover is available as long as your bicycle tooth tray is 42T, 44T, or 46T. To use this cover, you must have screws in the crank hole of your bike”

I have four unthreaded holes in my crankset.
I have a Merida Big Seven 300. I counted the number of teeth on the outside chainring(?) There are 40. The chainring is almost 17cm in diameter (including the teeth)

Or perhaps someone can suggest a better/easier alternative to stay clean?

My Norco came with a chain ring guard like that, and it does keep my pants off the chain ring, but it doesn't keep my pants off the chain. Due to that, I simply use a velcro strap around my pants leg on that side to keep my pants snug against my leg.

IMO, a chain guard that at least covers the top run of the chain and half of the chain ring is much better than a just a chain ring guard. But that's probably going to be something not easily mounted to your bike.


https://cimg1.ibsrv.net/gimg/bikefor...0eeceac5b7.jpg

dedhed 05-04-20 07:43 AM

What crankset does your bike have. Determine that and then what the BCD of the chainrings are and search "bashguard 40T XXX BCD" for whatever BCD your crank uses.

2cam16 05-04-20 07:45 AM

MRP makes some.

GeezyRider 05-04-20 07:57 AM

To go along with the advice from dedhed, here is how you measure the bolt circle diameter (bcd):

https://www.wolftoothcomponents.com/...e-diameter-bcd

You also will have make note of whether you have a 4 or 5 bolt pattern on the chanring.

2_i 05-04-20 09:23 AM

Fitting chain protection is notoriously difficult and depends on bike details. The options include placing an outer disk, and there following the directives of dedhed and GeezyRider, and/or mounting a chainguard that extends backwards over the chain. A good source for both is AliExpress but with long delivery times. Also a lot of browsing, looking at details, is required. Given low prices, long delivery times and high chances for mismatch, it is presumably advisable to order two or more solutions, hoping that at least one will work.

JackieYan 05-04-20 09:50 AM


Originally Posted by dedhed (Post 21454260)
What crankset does your bike have. Determine that and then what the BCD of the chainrings are and search "bashguard 40T XXX BCD" for whatever BCD your crank uses.

I'm not over technical on this. If I only knew what BCD means?
According to the Merida spec - if I'm quoting the right thing, it says FSA Alpha Drive, then "36-22 teeth". I 'don't understand that, as the front crankset has 3 "chainrings", and as I said that I counted the outer (largest) one which has 40 teeth.
I can attach a photo if you need - let me know, but this is the Merida page https://www.merida-bikes.com/en/bike/56/bigseven-300 if it helps?
Thanks.

dedhed 05-04-20 10:09 AM

https://www.qbp.com/diagrams/tech_co...crank/bcd.html

AlmostTrick 05-04-20 10:15 AM

I've ordered several bash guards from BBG, and have been very satisfied.

https://bbgbashguard.com/shop?olsPage=products

JackieYan 05-05-20 12:49 AM

Thanks dedhed and AlmostTrick for those two links.

I’ve had a look at the BCD for chainrings.
I measured the distance between the two holes (my FSA Alpha Drive has four)
It was 67/68mm, found it difficult to be certain.
To my mind, that gives a BCD of 94.73 for 67mm B measurement
or
a BCD of 96.15 for 68mm B measurement


Now looking at the BBG bashguard website, I see it has products listed by BCD. I want something larger than the BCD measurement, as that is less than the size of the whole chainring.
Am I right in guessing if ordering by BCD, the bashguard diameter allows for this, and is actually larger than the outside diameter of the crankset, so it overlaps the chain by a certain amount?

I can only see one 94BCD and one 96BCD.
The 94BCD has five mounting holes, so would I need the 96BCD, as that has four mounting holes like my crankset?

Next question: What is 30T or 34T? I need to select one of those. Is that something to do with the number of teeth?
The Merida spec says my FSA Alpha Drive has “36-22 teeth”. Again guessing that’s the middle and inner chainrings, as I counted 40 teeth on the outer one (not easy to count the other two).


As an aside, I've already contacted BBG to ask if they ship to Thailand, where I live. They do and ship via USPS for $14, although I don't know if that's surface or airmail (even if it's available right now?)

2cam16 05-05-20 07:35 AM

Usually the tooth count is etched on the chainrings. Check both sides of each chainring.

JackieYan 05-05-20 07:59 AM


Originally Posted by 2cam16 (Post 21456418)
Usually the tooth count is etched on the chainrings. Check both sides of each chainring.

Thanks for that bit of information.
So far I can see the largest one has "40T" on it.
The other two are more difficult to see, not only because you can't see all of the chainrings easily.. I'll try again in the morning in daylight.

Kapusta 05-05-20 08:13 AM

I suggest you do some googling to familiarize yourself with a few terms:

Double crankset (or 2x) vs Triple crankset (or 3x)

Chain-guard

Chainring

Crankset.

Also, look at your crankset and see if you can find a model number.

You are getting a bit of advise here from people who are not reading what you have written, and could lead you down the wrong path.

JackieYan 05-06-20 03:06 AM


Originally Posted by Kapusta (Post 21456493)
I suggest you do some googling to familiarize yourself with a few terms:

Double crankset (or 2x) vs Triple crankset (or 3x)

Chain-guard

Chainring

Crankset.

Also, look at your crankset and see if you can find a model number.

You are getting a bit of advise here from people who are not reading what you have written, and could lead you down the wrong path.

Which of the terms do you think I haven't understood (it's a straight question).

I have an image of a bicycle I downloaded to find the names of the parts, as I didn't know them, and have used those names.
The heading I used "Chain Ring Guard/Chain-wheel Protector" was copied from an eBay advert, as I wasn't sure of the name of the item at the time.

The double crankset and triple crankset I follow, as that's the number of chainrings on the crankset.
What I don't understand is from the Merida spec, it just says "FSA Alpha Drive" and below it "36-22 teeth"
That indicates to me it's a double crankset? Yet it has three chainrings, the largest being 40T.

You asked if I could see a model number. did you mean other than the Merida listed one, which it says on the chainring and the crank arm ? - "FSA Alpha Drive"
On the 40T chainring it says "M-10", if that's relevant?

I've tried to see the number of teeth stamped on the other two chainrings. I just can't get at them to see, and short of taking every apart, trying to clean them isn't easy as they are both overlapped by the 40T one.

AlmostTrick 05-06-20 04:40 AM

You don't need to know the tooth count of the smaller chainrings. You only order based on largest ring tooth count and BCD. (and 4 or 5 bolt, obviously!) Some like to run a slightly larger (higher tooth count) bashguard for a little extra protection. I've done this at least once.


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