Thorn 38T 104BCD 4 arm front chain ring with Hebie Chainglider

[martinf]

In my case, in very dusty/sandy and windy environments, the Chainglider was simply unable to prevent grit from entering.

This is something I considered. Dry dust isn't usually a problem where I ride, but I did encounter it several years ago before I started using Chaingliders. The chain got coated in orange laterite dust, and a few hundred kms onwards it was so worn that I changed it.

I think a Chainglider would slow down the entry of dry dust, that might be enough for short stretches of dusty track. If I encounter this situation again, I will probably just open the Chainglider afterwards, and then check the chain, then if I reckon it is too dirty either try and clean/relubricate (difficult to do this properly while touring) or simply fit a new chain.

I doubt I will do any touring with long stretches of dusty tracks, but my "solution" would be to remove the Chainglider and strap it to the pannier rack rather than chucking it away, so I could refit it after changing the chain and getting back to somewhere with more normal conditions.

The Chainglider doesn't keep water out either, but it does a reasonable job of keeping mud and wet sand off the chain in the Atlantic weather conditions I usually ride in.

I generally check the chains on my Chainglider equipped bikes once a year, and often don't need to do anything to the chain. The exception was when I was doing survey work in the winter just before I retired, this entailed about 8 hours a day on the bike, much of it on wet muddy tracks. I opened the Chainglider once a month to check, and sometimes cleaned/relubricated the chain. Before I got Chaingliders, on similar work I would clean/relubricate the chain every weekend and the chain/sprockets lasted between 3 and 4 weeks.

[Andre Jute]

+1 to Martin's post immediately above.

What we haven't considered yet is that a cover for the Gates Drive belt and wheelies will probably let in dust and damp, same as the Chainglider*, same as every other "full" chain enclosure. If it lets in both -- and for those who have no desert experience, there's dew every morning in the desert because the nights are bleeding cold -- it seems likely to me the mess might be worse to clean up than not having a cover at all and simply letting the sun dry off the belt.

*Yes, I know, we haven't heard that it bothered anyone; the experience is that amazingly little gets into the Chainglider, but still, sometimes submersion is unavoidable and even just in persistent rain, water always finds a way in if it is there to be found.

[Captain Bubble]

Hi, Is anyone successfully using the above combination? Do the chain ring bolts of this 38T chain ring foul the chainglider?
Many thanks.

I use 110BCD 5-arm cranks with 38T chainrings (on several bikes) and the  chain ring bolts don't foul the Chainglider.

I haven't tried them, but 104 BCD is smaller than 110, so 104BCD 4 arm cranks should be OK.

Thank you for your reply. This is what I was hoping to hear from some one with hands on experience. I shall give the 38T 4 arm 104BCD chain ring a go. I thought it would work just wasn't sure. Don't want to spend yet another £40-50 on a chain ring that isn't going to work. Many thanks.

[Captain Bubble]

Many thanks to those who have offered advice, suggestions and links to help me with my query.

For those who have taken the thread into a discussion on the merits of the Chainglider, chains and belts it has been interesting, but maybe this is a discussion worthy of another thread?

Thanks again.

[WorldTourer]

This is what I was hoping to hear from some one with hands on experience. I shall give the 38T 4 arm 104BCD chain ring a go.

You did hear from someone with hands-on experience: me. I told you that that setup will not work with the Chainglider, and not because of the bolts but because of the thickness of the Thorn chainring.

I just checked my SJS order history to confirm that it was those particular parts that proved incompatible with the Chainglider, forcing me to use an entirely different chainring and cranks, and indeed:

• Thorn 104mm BCD 4 Arm Reversible Single Chainring 3/32 Inch - Black
• Thorn 104/64 PCD Triple Crankset MK2 - Black

And that chainring is 38T. I have found this to be the best Rohloff ratio for my needs.

[martinf]

You did hear from someone with hands-on experience: me. I told you that that setup will not work with the Chainglider, and not because of the bolts but because of the thickness of the Thorn chainring.

WorldTourer is correct that a Thorn chainring is thick. And it will rub on a Chainglider*.

Surly stainless-steel chainrings are much thinner, and the ones I have work well with a ChainGlider.

But AFAIK Surly don't do 38T in the 104 BCD 4 bolt size.

So to avoid rubbing you would need to get something other than a Thorn chainring.

* Whether the rubbing is a problem or not can be debated. Two of my Chainglider equipped bikes have rather thick TA 1/8" width chainrings (and 1/8" chains and sprockets). These rubbed on the Chainglider at first, but apart from the rather faint noise, did not seem to cause much friction. After a few hundred kms, the plastic on the Chainglider wore to fit the chainring and the rubbing noise stopped.

Other people have had different experiences, notably with the thick Thorn chainrings.


 

[martinf]

I already have a chainglider working well on a 42T Thorn chainring with 5 arm 140BCD crank (FSA).

If the 42T ring is not too worn and is already working well in the ChainGlider and you have a 16T sprocket it seems to me that the easiest solution would be to get a 17T sprocket rather than a smaller chainring.

The Rohloff-specific ChainGlider rear section is compatible with 15, 16 or 17T sprockets.

[JohnR]

You did hear from someone with hands-on experience: me. I told you that that setup will not work with the Chainglider, and not because of the bolts but because of the thickness of the Thorn chainring.

WorldTourer is correct that a Thorn chainring is thick. And it will rub on a Chainglider*.

Surly stainless-steel chainrings are much thinner, and the ones I have work well with a ChainGlider. But AFAIK Surly don't do 38T in the 104 BCD 4 bolt size.

So to avoid rubbing you would need to get something other than a Thorn chainring.

See my posts further up the thread with (i) a link to a UK source of steel (but not stainless) 104BCD chainrings which work fine with a Chainglider and (ii) a photo of a 38T version of one of those chainrings showing that the bolts will be well clear of the teeth.

I've noticed that there's now a hint of rust on the corners of the steel chainring and will make an overall assessment of the condition when spring arrives. I'm sure it won't rust away before it gets changed to another giving lower gearing (probably 38/16 instead of the current 42/17) to keep my legs happier.

[leftpoole]

I have been 'tempted' at times to respond to this post and current 'talk', but I have no idea what is being discussed!!!

[crg]

I bought a Thorn 38T 5 arm 130 BCD chain ring already but hastily over looked the fact that because it's a smaller ring then the chain ring bolts are correspondingly nearer the edge on a 130 BCD 5 arm crank. The chain ring bolts sit proud of the surface of the chain ring itself and will foul the chain glider case as the chain ring rotates inside.

The chainglider is supposed to fit all 38t chainrings. Did you contact Hebie? What was their response?

[Matt2matt2002]

I bought a Thorn 38T 5 arm 130 BCD chain ring already but hastily over looked the fact that because it's a smaller ring then the chain ring bolts are correspondingly nearer the edge on a 130 BCD 5 arm crank. The chain ring bolts sit proud of the surface of the chain ring itself and will foul the chain glider case as the chain ring rotates inside.

The chainglider is supposed to fit all 38t chainrings. Did you contact Hebie? What was their response?

I think there can be an issue with chainring thickness and the Chainglider
When I  fitted my first one it coincided with me fitting new front ring and rear sprocket. And I recall being advised by some folks here to go for a thin front ring.

I'll look up my stats and recorders soon to clarify this.

Best

Matt

Edit: Front chain ring and Chainglider fitted Oct 2014

[JohnR]

And I recall being advised by some folks here to go for a thin front ring.

As a Chainglider user I've just fitted a nice 2mm thick stainless steel Bikepunx chain as reported here http://thorncyclesforum.co.uk/index.php?topic=14229.msg110802#msg110802. It seems to be running more smoothly than the 2.4mm thick steel chainring that I had been using (but dirt and some corrosion effectively increased the thickness and made its surface less smooth).

[crg]

I bought a Thorn 38T 5 arm 130 BCD chain ring already but hastily over looked the fact that because it's a smaller ring then the chain ring bolts are correspondingly nearer the edge on a 130 BCD 5 arm crank. The chain ring bolts sit proud of the surface of the chain ring itself and will foul the chain glider case as the chain ring rotates inside.

The chainglider is supposed to fit all 38t chainrings. Did you contact Hebie? What was their response?

I think there can be an issue with chainring thickness and the Chainglider
When I  fitted my first one it coincided with me fitting new front ring and rear sprocket. And I recall being advised by some folks here to go for a thin front ring.

I'll look up my stats and recorders soon to clarify this.

Best

Matt

Edit: Front chain ring and Chainglider fitted Oct 2014

Not the chainring thickness but the 130mm BCD.