Chainring guard or bash guard installation

[rpesq]

Hi,

I am buying a new bike, it has a Shimano FC-5703 triple ring crankset, 50X39X30T, bcd 130mm.

I am a casual rider, and really want some type of chainguard on here so that I can ride in jeans without need for a leg wrap to keep my pants leg out of the chainrings.

I do not know what the difference is between a "bash guard" and a "chainring guard / "chain guard".

Regardless, what is the best way to accomplish some type of chainguard on here?  What will I need?  I can find chain guards sold on ebay made by Driveline, but is that the correct way to go?  If so, how do I install it and what will I need in the way of tools?

I would prefer to keep all 3 chainrings if possible, but if not, how difficult is it to remove the largest chainring on this FC-5703 and install a chainguard/bashguard?  I really would like to avoid removing the whole crank assembly or crank arm.

Thanks in advance,
rpesq

[nfmisso]

wnload and look at this Shimano techdoc:  EV-FC-5703-3004B

which shows you how it goes together.  You will need to remove the five item 13 bolts.  For the outside you will need the tool that fits the head.  On most this is a 4mm hex key, but it appears that Shimano uses Torx on some.  For the back side I usually use a very wide bladed screw driver - but I always remove the right crank arm to install the chain guard.

The Driveline chain/bash guards are premium products, very well made, and nice looking.  You can use a 50T 130mm BCD, or a 52T 130mm BCD for your application.  On our tandem, we have a 54T big ring, and used a Driveline 56T model.  

The Driveline chain/bash guard comes with the required hardware to mount it to the outside of the big ring so that you do not give up the triple.  You can also mount it in place of your big ring, using the hardware that is currently on your crankset.  The Driveline hardware is longer versions of item 13 shown in the above document - the Driveline hardware uses a 4mm hex key, plus five spacer to position the chain guard away from the big ring.

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Here is one of my installations  [img]http://[/img]

[rpesq]

Hi Nigel,

Thanks for the excellent reply.

Let me ask your opinion... I never use the large chainring because of the type of riding that I do (lower speeds, lots of hills).  Knowing that, do you think it is smarter to just replace the 50T chainring with a guard?  (The only reason I thought about keeping all 3 chainrings was fear that installation would be more difficult if I were to remove one of the rings, but it seems as though the 50T ring will be basically disconnected with this installation anyway?)

If yes that it makes sense to just replace the 50T with a guard, I imagine that it would be smart to size the bashguard according to the middle chainring, in this case, a 39T? -- since that would be the biggest chainring that would be installed.

If I were to replace the 50T chainring, is the Driveline guard good enough quality, or should I go with something different.  I see FSA makes them, and I see surplus Shimano Alfine FC-S501 39T chainring guard on ebay for $10 shipped.  Not trying to save money but just get something that will mount easy and with good build quality.

I know that I would have to adjust the FD to prevent it from shifting into the large chainring, I believe my adjusting the H screw to limit travel.  I think my chain should be fine, as I cannot see why anything would have changed as the gear that I always use would still be what I always use.

FYI - I bought a Park Chainring nut wrench tool last night, which should make removing those 5 screws a little easier.

[nfmisso]

You are going to remove both the middle and big ring during the installation of the chain guard.  It is the same amount of work to put things back together if you keep or remove the big ring.  The only benefit I can see from removing it is loosing a few grams - you could shave your head and get the same savings.....

The downside of removing the big ring is adjustment of the FD - I do not know if you can screw the H limit screw in far enough.

The Driveline ones are top quality.  There are no better.  Some of the other branded ones (FSA) appear to be made by the same company - the CNC machining is identical.

I would keep the triple, as it is less work (no FD adjustment) and less risk (FD adjustment range might not be enough); and go with a 50T or 52T guard.  Color choice may drive you to 50T or 52T.  Note that the one in my picture is a 53T chain guard with a 52T ring behind it.

[rpesq]

Solid advice, thank you very much!

I will go with your suggestion, keep the 50T and use a driveline 50T guard (which is available in the color that matches my bike, black).

[dbower]

I recently ordered a driveline guard for my 48T chain ring.  Unfortunately, doesnt look like any of the mounting holes line up... my fault for not verifying before ordering.

Does anyone know if there is a guard compatible with my ring shown in pics?  All the driveline stuff seems like the BCD is too small.  The mounting holes on mine are on the large outer ring, around 7" BC, whereas drivelines are 104mm (4")


[img][/img]



Any help greatly appreciated.

[GeorgeET]

You do not show picture of the guard, but if its like the one in photos above made to mount to the crank and you cannot get one that mounts to the rings you either need to drill new holes in the guard or get a new crank. Holes are cheaper.

[dbower]

(01-21-2017, 07:08 PM)GeorgeET Wrote:  You do not show picture of the guard, but if its like the one in photos above made to mount to the crank and you cannot get one that mounts to the rings  you either need to drill new holes in the guard or get a new crank. Holes are cheaper.

Thank you, yes the guard is similar to this one...

Will need the smaller hardware as well, as the ones that came with the guard are too big for the holes in my ring.

[nfmisso]

Sorry; I am not aware of any CG that will fit your current rings, without so drilling.

If you are up to it, I'd go with a 48T, BCD 110mm unit like this one:
http://www.ebay.com/itm/Driveline-Chain-Guard-48T-BCD-110mm-110g-Black-/140922746198?hash=item20cfa67556:g:ocgAAMXQ~TtRLhPt
Drill and tap M6 holes in your present outer chainring, and use spacers and M6 button head screws which will fit nicely in the counter bored holes of the Driveline CG.

Alternatively, just get a new crankset with CG like this one:
https://www.amazon.com/Shimano-M131-Crankset-170mm-48/dp/B003ZMDJW6/ref=sr_1_1?s=outdoor-recreation&ie=UTF8&qid=1485050870&sr=1-1&keywords=m131

It uses a 122mm (±2mm is okay) bottom bracket - measure what you have.