RodTi Posted June 21, 2011 Posted June 21, 2011 So after doing the SS conversion recently, noticed that the rear skewer - which has seen better days - has developed what can only be called a "bend" on the end of it, where the thread is, as it screws into the adjustment cap. Needless to say, it's not something I'm particularly comfortable riding on. Bought a Shimano cheapie as a replacement this afternoon - took the longest one on the rack - 163mm.Came home, and realised it was still a wee-bit shorter than the current one. Had a look over at all the local online shops, and then CRC - and none of them appear to indicate skewer lengths. The only one that does, is made by DT Swiss, and comes in at just under R150.00 - which isn't too bad, I guess. I'll probably have to order it, since it's the only one I could find that has a 170mm option. With this being said:Is there a standard length for skewers? Why don't they list their lengths?And why does anything from 165mm upwards appear to be so rare these days - or has it always been a bit of an odd/unnecessary length?
Johan Bornman Posted June 22, 2011 Posted June 22, 2011 Skewer length is a function of hub width. Road bikes have a 130mm Over Locknut Dimension (OLD). Add 8mm per side for drop-out thickness and 14mm for skewer nut width and you have 160mm. MTBs are 135mm in OLD and will thus require 165mm. Tandems 145mm etc etc. Perhaps your dropouts are a bit thicker? I measured a couple of Shimano MTB skewers here and they're all 160mm. Hope skewers are 170mm and requires lopping for road bike use. Hope skewers in pairs are about R340-00, IIRC.
RodTi Posted June 23, 2011 Author Posted June 23, 2011 Skewer length is a function of hub width. Road bikes have a 130mm Over Locknut Dimension (OLD). Add 8mm per side for drop-out thickness and 14mm for skewer nut width and you have 160mm. MTBs are 135mm in OLD and will thus require 165mm. Tandems 145mm etc etc. Perhaps your dropouts are a bit thicker? I measured a couple of Shimano MTB skewers here and they're all 160mm. Hope skewers are 170mm and requires lopping for road bike use. Hope skewers in pairs are about R340-00, IIRC. Thanks JB. The OLD has been effected by the SS tensioner that has been installed. It has a tab that the skewer must run through on the outside, in addition to the dropout - and it's no doubt what has thrown out the width... Good to know that the Hope's are also 170mm. Will move this thread over to the SS forum - since others might use this same tensioner, and it appears to be worth considering that a skewer might need to be replaced as well...
RodTi Posted July 11, 2011 Author Posted July 11, 2011 Not a very happy chappy at the moment! Geared bike is in for a lengthy service - and have been hitting the trails on the SS... Been killing myself getting up the local hill - but things are slowly improving! Thing is - the appeal of having a maintenance freeless-so ride in a SS, is beginning to fade ever so slightly... The tensioner I have installed, is doing a pretty poor job of providing tension... I regularly have to hop off and re-tighten the bottom bolt, inevitably just at the bottom of a long uphill... This happens before I've even started standing, and I've been particularly mindful of not mashing the pedals, but ensuring an even, constant rotation in my pedal-stroke... The skewer-length problem highlighted above, is also providing its own issues... Even with a max skewer-length of 170mm, the end threaded/adjustment-cap of the skewer simply doesn't get enough bite on the skewer-thread... The wheel is somehow shifting during the ride, with the result that by the time I'm almost home, the rear-wheel has developed brake-pad rub... In the absence of a longer skewer - I presumably have three options: 1.) Start looking at different tensioners, that do not make use of the (red-circled) tab (as above); 2.) Have an machine shop alter the threaded/adjustment-cap of the skewer, to remove the inset-depth of the thread 'bite' on the cap, thereby 'regaining' the mm's lost to the (red-circled) tab; or 3.) find my golden ratio and loose the tensioner... Joy.
Seadog Posted July 11, 2011 Posted July 11, 2011 Have a look at this tensioner...Looks like it bolts to your dropout, which may solve the problem? Am I right here? http://www.chainreactioncycles.com/Models.aspx?ModelID=7169 http://www.chainreactioncycles.com/Images/Models/Full/7169.jpg
RodTi Posted July 11, 2011 Author Posted July 11, 2011 Have a look at this tensioner...Looks like it bolts to your dropout, which may solve the problem? Am I right here? http://www.chainreactioncycles.com/Models.aspx?ModelID=7169 http://www.chainreactioncycles.com/Images/Models/Full/7169.jpg Thanks R4YL... Went and had a looksie - terrible reviews though... Fire Eye's The Spur II might be an option... but that's starting to look quite complicated for a tensioner, and would take away from the clean look I'm trying to get at on the bike... I'm going to have a closer look during the week at what my options are... expect a few pics up here soonish, to throw it open to the Hub for some fire and brimstone...
nathrix Posted July 11, 2011 Posted July 11, 2011 I have a Surly Singleator Single Speed Chain Tensioner."Spring loaded chain tensioner for running Single Speed on non-adjustable chain tension frames.Fit to rear mech hanger position.Surly Singulator features CNC alloy body, variable chainline, floating tension pulley, stainless steel pivot bushing, Triple sealed reversible spring.Compatible with 1/8" and 3/32" chains.11T jockey and slotted alloy chain rejection side plates.All in all... the mutts nutts of SS chain tensioners." I purchased mine at http://www.wiggle.co.uk/surly-singleator-chain-tensioner/
The Drongo Posted July 11, 2011 Posted July 11, 2011 (edited) Been killing myself getting up the local hill :thumbup: The tensioner I have installed, is NOT ??? doing a pretty poor job of providing tension... I regularly have to hop off and re-tighten the bottom bolt, inevitably just at the bottom of a long uphill... RodTi - Which one is "the bottom bolt" in the illustr? The skewer-length problem highlighted above, is also providing its own issues... Even with a max skewer-length of 170mm, the end threaded/adjustment-cap of the skewer simply doesn't get enough bite on the skewer-thread... The wheel is somehow shifting during the ride, with the result that by the time I'm almost home, the rear-wheel has developed brake-pad rub... Joy. RodTi. The locator on the tensioner; that the skewer passes through; is that up against the frame between the acorn nut and the frame, cause if it is then you are getting no 'bite' into the frame and it is simply going to slip around in the dropout (I am assuming you have horizontal dropouts?) You got a pic of it fitted? ??? Edited August 23, 2011 by RodTi
RodTi Posted July 11, 2011 Author Posted July 11, 2011 I have a Surly Singleator Single Speed Chain Tensioner."Spring loaded chain tensioner for running Single Speed on non-adjustable chain tension frames.Fit to rear mech hanger position.Surly Singulator features CNC alloy body, variable chainline, floating tension pulley, stainless steel pivot bushing, Triple sealed reversible spring.Compatible with 1/8" and 3/32" chains.11T jockey and slotted alloy chain rejection side plates.All in all... the mutts nutts of SS chain tensioners." I purchased mine at http://www.wiggle.co.uk/surly-singleator-chain-tensioner/ Thanks Nathrix... Good reviews up on Wiggle... this might be what I'm looking for.... It simply slots into/onto the hanger, I presume - so no tabs etc. that also require adjustment/fitting via the QR skewer?... I'll have a good look at my current tensioner over the week, and see if I cannot remedy the situation effectively, and cheaply... Failing which, might take the Wiggle option...
nathrix Posted July 11, 2011 Posted July 11, 2011 Thanks Nathrix... Good reviews up on Wiggle... this might be what I'm looking for.... It simply slots into/onto the hanger, I presume - so no tabs etc. that also require adjustment/fitting via the QR skewer?... I'll have a good look at my current tensioner over the week, and see if I cannot remedy the situation effectively, and cheaply... Failing which, might take the Wiggle option...It slots onto the hanger. It took me 5 minutes to adjust the chain and install (shortening the chain and adjust the tensioner).
RodTi Posted July 11, 2011 Author Posted July 11, 2011 RodTi. The locator on the tensioner; that the skewer passes through; is that up against the frame between the acorn nut and the frame, cause if it is then you are getting no 'bite' into the frame and it is simply going to slip around in the dropout (I am assuming you have horizontal dropouts?) Nope - vertical dropout. The 'locator' has a sort of oval part extended off the back of it, which fits into the dropout slot. As you correctly point out, the arrow points to the scuff marks on the frame, where the acorn-nut/adjuster-cap used to 'bite' into the frame... The locator's extended part now presumably takes care of this, by fitting into the dropout slot... The nut now 'bites' onto the flat part of the locator, and the width of the locator now sees the acorn-cap a few mm's further 'away' from the end of the skewer, if you follow what I'm trying to say, which sees it get less 'purchase' on the skewer thread... The locator isn't visible on the photo, but it's in between the acorn-cap and the actual frame - in the 'gap' pointed at by the arrow... The yellow circle is the bolt I'm needing to tighten 2/3 times a ride... It controls the 'pivot' on the tensioner... It's not a particularly long bolt, and has no 'nut' on the back of it... Thinking a nut of sorts might help secure it better??
RodTi Posted July 11, 2011 Author Posted July 11, 2011 Thanks Nathrix! The Drongo - see below: In the middle is the 'bolt' that constantly needs tightening...You can also see the back end of the 'tab'/locator - the part that fits into the dropout slot... The wheelnut has bit into it, causing the abrasions you see on it, following its oval shape. Below is the adjustment/acorn-cap... Notice how the thread-hole is recessed? I'm thinking of getting a shop to machine the top edge down a tad [or cue hack-saw ], which will effectively reduce the 'recess' of the cap, thereby nullifying the width inserted between the skewer thread and the cap by the tensioner-tab/locator... What you think?
RodTi Posted July 12, 2011 Author Posted July 12, 2011 So I had a look around at various sites last night, getting a feel about tensioners and the like. Appears that they can be categorised, broadly, into two main categories - namely those that attach at the back - and those that are connected near to/on the BB. Of those at the back, they either - a.)dial/slot/screw only into/onto the existing hanger; orb.)as above AND are attached/connected to the QR skewer slot as well (like the one I have). With this being said - and based purely on my reading of various review placed up by cyclists over several years, on various sites - the following becomes apparent: 1.) Irrespective of the make or model, home-made/modified or bought new - almost all of them have users reporting issues pertaining to "loss of tension"... 2.) The above applies irrespective of whether the pulley/tensioner pushes up or down on the chain.3.) Many comments are made regarding "having to re-tighten the bolt" - with these being spread out over those who occasionally do it whilst routinely cleaning the bike at home, or those who have to make adjustments whilst on the bike/trail. In short [], it appears that whilst there are obviously those that are fortunate in having no problems - there are plenty of SS riders who have issues with tensioners... Many of the replies to above, suggested the user check chain alignment and setup issues (as per the instructions of the specific tensioner)... However, there are those who record being 100% certain that all is as it should be, and it taking experimenting with 2/3 models before finding one that worked for them... Given that the magic ratio (thereby negating the need for a tensioner) apparently works a treat until your chain eventually starts stretching [] - for those who do not have the option of horizontal dropouts - the tensioner is a unavoidable part of the setup... I have now learnt that I should probably have gone for something like the Surly Singulator (or similar), as it being an example of a.) above, would not have interfered with my skewer... With this being said - the Surly also comes standard with a tension spring - whereas my current tensioner relies on its adjustment bolt 'staying put', as it were.... I will therefore try my hand at modifying what I have, and will look a-fresh as building my own from an old rear mech I have lying at home. Suffice it to say - if you're converting to a SS - put some thought into what tensioner you are going to purchase, since once the conversion is done, it remains the only part that could require continued 'adjustment-input' going forward - and if this can be avoided by choosing the right tensioner, then by all means, try and do so!
divernick Posted July 12, 2011 Posted July 12, 2011 I use the gusset achelor with absolutely no issues. It's quiet and once it's tightened to the mech hanger and I have closed the QR it works like a charm. It comes with it's own skewer nut that replaces the stock one so that it fits properly. No springs, jockey wheels, grub screws etc. http://tfe.me/image/480_345/gu1835.jpg
RodTi Posted July 12, 2011 Author Posted July 12, 2011 (edited) I use the gusset achelor with absolutely no issues. It's quiet and once it's tightened to the mech hanger and I have closed the QR it works like a charm. It comes with it's own skewer nut that replaces the stock one so that it fits properly. No springs, jockey wheels, grub screws etc. http://tfe.me/image/480_345/gu1835.jpg Hey DN - like the idea that it comes with it's own skewer nut, presuming that unlike the standard nut, it has little to no recess? It's design though is pretty similar to the one I have on - and mine isn't working... As mentioned, I need to constantly tighten up the adjuster bolt, since it eventually loses tension and pivots away from the chain.... Thinking about it some more - does the skewer nut offer additional force to prevent the pivot? I suspect that's where I'm picking up the problems on my one... With my skewer nut not being able to 'bite' up against the locator tab as much as what it probably should - it might be why the tensioner is able to pivot as easily as it does... Guess the skewer nut in addition to the adjuster bolt would work at keeping the tension up?? Edited July 12, 2011 by RodTi
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