SPD pedal compendium

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Brucey
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Re: SPD pedal compendium

Postby Brucey » 25 Nov 2020, 4:19am

It isn't as simple as v1 and v2 concerning bindings. If you go back a few pages I have grouped the pedals according to which cleats they were originally specified to use. Group A contains PD-M737, PD-M525, PD-M323 pedals which were originally designed for SM-SH50 and SM-SH55 cleats, and there is a difference in the bindings in the next group of pedals which were designed to accept SM-SH51(v1) and SM-SH55 cleats, which included PD-A525, PD-M535, PD-M636, PD-M747. Even within each group there are variations in how the bindings operate, but there are major differences in pedal operation depending on which cleats they were originally designed to use.

You will note that I refer to SM-SH51 cleats with a v1 or v2 suffix. This is because there are two different cleats with the same part number. Currently you can only buy the second sort. Pedals work differently with each version of the SM-SH51 cleat.

Reshaped cleats provide a good way of customising the amount of float and release characteristics. Cleats wear anyway and shimano recommend a new set every year or so if you ride much. However the pedals wear too and this of course also influences how the bindings work. Float is usually 'easy' float, i.e. the jaw springs are still holding the cleat lengthwise. Once the cleat is twisted past a certain point the jaws start to be forced open and this may be considered to be the limit of the easy float. However if the jaws and/or the cleat are worn, the float may become both freer and greater in extent.

Zenitb's photos show there should be different amounts float in different directions; if the cleats are new, this is a sure sign of worn pedals; none are designed with asymmetric float (although some do have asymmetric release characteristics). Roger's PD-M737s could be worn too, perhaps. As i have commented previously, float is a very personal thing; as long as you have enough (for you) then pedals might feel 'about the same' in use. However if there is even one degree less float and you nudge into the limit whilst pedalling, the result can be excruciating pain which may develop over a period of time whilst riding.

Note that in some early pedals (with a flat front jaw) the float is limited by the width of the bottom of the cleat nose; a small scallop in the cleat here can increase the available float in that pedal type only.

Most cleats are nominally 34.0mm long (where the jaws hold them). Most SPD pedals have jaws which close to 33.0 to 33.5mm when they are new. Pedals which have gone though a few sets of cleats tend to have worn jaws; both the jaws themselves wear (when releasing and whilst pedalling if you use/need the float whilst pedalling) and the jaw stoppers wear too, because every time the cleat is released the moving jaw(s) slam(s) into the stopper. The former type of wear increases the jaw opening and the latter reduces it. Normally the jaws wear faster than the stopper, but this isn't guaranteed. With new cleats, worn pedals may feel 'normal' even when the jaws are worn such that the opening is between 33.5 and 34.0mm, but in the latter case the slightest cleat wear will soon change the feel of the pedal.

The jaws also wear in two other main ways; laterally (so as to influence the extent of float, and/or the release) and vertically (which affects how noisy the pedals may become and again the release characteristics. You can infer lateral wear by how much float there is each way and (in pedals which ought to have a symmetric release) how the release is in each direction.

Vertical jaw wear is much more difficult to characterise, since worn (worn to be thinner) cleats and worn shoes (e.g. worn where the jaws contact the sole) can also allow the cleats move vertically in use. However in extremis some pedals can measure within spec for jaw opening, and even with new shoes and new cleats, a SM-SH51 cleat can still move vertically and/or release more like a SM-SH56 cleat; this normally means the jaws are vertically worn. This form of wear limits the working life of SPD pedals for some riders.

Most forms of cleat and jaw wear make for more/easier float and an easier release. However there is one form that does not make release easier; if you use the float when pedalling the rear of the cleat may develop a groove where the jaw bears against it. This groove impedes the vertical movement of the cleat and if (through design, wear, or cleat compatibility) the pedal doesn't have functional 'kicker ramps' (which force the rear of the cleat upwards when twisted) the release can be impaired.

Anyway the bottom line is that if you fit current cleats to older pedals (which is probably more likely than older cleats in newer pedals) you may get reduced float, depending on the detail of the design/manufacture of the parts and how worn the pedals are. Few such combinations are inherently dangerous per se (an obvious exception being the use of SM-SH50 or SM-SH55 cleats in 'open' binding pedals) so have at it. If the amount of float is tolerable for you then great. If it is not, a few (usually simple) modifications to the cleat may sort it out.

cheers
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~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~

zenitb
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Re: SPD pedal compendium

Postby zenitb » 25 Nov 2020, 8:09pm

rogerzilla wrote:New SH51 cleats work fine with original M737 pedals, giving a bit of float and feeling much the same as a new M540.

SH51 cleats in almost-original M525 pedals give zero float (the rear latching plate has a V-shaped cutout, not the usual rounded one).


Interesting Roger - I would be keen to see the shape of the rear latching plate.. as you can see from my pics earlier my PD-M323 pedals of this vintage have a curve-flat-curve type compound shape. I have two sets of these PD-M323 pedals and they are both of this shape...
Last edited by zenitb on 25 Nov 2020, 8:41pm, edited 1 time in total.

zenitb
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Re: SPD pedal compendium

Postby zenitb » 25 Nov 2020, 8:34pm

Brucey wrote:It isn't as simple as v1 and v2 concerning bindings. If you go back a few pages I have grouped the pedals according to which cleats they were originally specified to use. Group A contains PD-M737, PD-M525, PD-M323 pedals which were originally designed for SM-SH50 and SM-SH55 cleats, and there is a difference in the bindings in the next group of pedals which were designed to accept SM-SH51(v1) and SM-SH55 cleats, which included PD-A525, PD-M535, PD-M636, PD-M747.

Ok I have gone back and edited the post to remove the v1/v2 nomenclature from the bindings. I will go back and put "Group A" and "Group C" against the two pictures (NOW DONE) so we are compatible and so it doesnt confuse readers of the thread !!! :-)

(one PS on that though is that I am probably going to query the PD-M747's membership of Group B. I still have this pedal (my first Shimano SPD) and on my sample I see no difference in binding shape from my PD-M515, which as I am sure you know is a cost reduced version of the same pedal - I will post some pics up in a bit .. and I suppose I could do another static float test)

Brucey wrote:Zenitb's photos show there should be different amounts float in different directions;

OK this is where I think I have misled you Brucey, apologies for this. My photos were "straight through" and "heel in". I was being lazy and because I am a heel in cyclist that was the only float direction I recorded. To avoid misleading more people I have gone back to the post and amended it with the "heel out" float as well and you should be able to see its pretty symetrical .. and that my PD-M323 and PD-M324 now at least have similar amounts of float.

Brucey wrote:Note that in some early pedals (with a flat front jaw) the float is limited by the width of the bottom of the cleat nose; a small scallop in the cleat here can increase the available float in that pedal type only.
cheers

yes I noticed that with the PD-M323s when I was photographing them. Its as if for the Group A pedals they spit the function of vertical location and lateral location at the front as if they wanted to be able to control these separately in the cleat. As you say in later binding designs the front claw performs both functions.

Interesting discussion.. mainly of use to those of us resuscitating old pedals I guess !!!

zenitb
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PD-M747 vs PD-M515 binding shapes

Postby zenitb » 25 Nov 2020, 9:34pm

My copy of the PD-M747 looks like the PD-M515 I have. My view (at least of my copies) is that they both belong in "Group C". They are not identical, the latch is a slightly different pressing I think but the connection points are both circular in the "Group C" style. I have never had issues using SM-SH51 cleats in the PD-M747 in fact its superb performance is what sold me on the whole Shimano SPD range. See what you think ...

P1040994.JPG
PD-M747

P1040993.JPG
PD-M515


..awaiting repair though ... too many rock strikes :-(
Broken PD-M747.JPG
PD-M747 broken binding

Brucey
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Re: SPD pedal compendium

Postby Brucey » 25 Nov 2020, 10:24pm

the groupings I worked out are based on the cleats that shimano specified when the pedals were released, according to the EV techdocs and the SI techdocs available. This includes not only shimano's online database but also my repository of paper shimano techdocs (which is about a foot thick) and various internet archives of old techdocs which shimano have withdrawn.

I happen to have an almost unused set of PD-M747 and I indeed expected the bindings to be identical to PD-M515 (a pedal I know very well indeed). I was surprised to discover that the PD-M747 bindings did not behave in the same way and in fact are slightly different, giving significantly reduced float. This mystified me for a long time until I worked out which cleats were specified for use with these pedals originally and the whole SM-SH51 v1 vs v2 business (which shimano have never owned up to BTW). [It is also possible that shimano varied the design of the pedals (within any one model) over time; the date codes for the pedals in the photos above are XA (jan 1999) and ZH (aug 2001) for the PD-M747 and PD-M515 pedals respectively; I can compare with examples I have of each. ]

In the very first post in this thread I could (in fact should, probably) have added which cleats are meant to work with each pedal but I fudged it by saying you should check the instructions with each pedal and act accordingly. But it turned out to be a bigger topic than I expected and of course I was unaware of the SM-SH51 v1 - v2 thing.

Re the float in each direction in zenitb's photos; I could see that the one photo was centred and the other not, but in the 'centred' photos it seems like the lateral clearance (eg of the cleat nose) isn't the same each side, suggesting that the float won't be either. If I get round to measuring float properly I shall probably build a contraption which allows the angle of cleat movement to be measured directly. To my surprise (not to mention annoyance) I found there was enough distortion in some photos I took to render measurements off photos inaccurate. in the tests I have done so far the difference between SM-SH51 v1 and v2 cleats is smaller than I expected but it is still there.

edit; photo below comparing PD-M515 and PD-M747

Image01959.jpg
PD-M515 (left) vs PD-M747 (right)


cheers
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~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~

Brucey
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Re: SPD pedal compendium

Postby Brucey » 26 Nov 2020, 12:41am

FWIW it seems there are two different versions of the PD-M747 pedal. The first version has a thin rearward extension to the 'platform' which acts as a stopper plate for the rear jaw, and is the version I have photographed in my previous post. This 1995 techdoc shows the same arrangement.

Image

however the only techdoc on shimano's site for PD-M747 shows a later version with different parts in the mechanism, which is what zenitb appears to have.

https://si.shimano.com/api/publish/storage/pdf/en/ev/PD-M747/EV-PD-M747-1521B.pdf

so possibly the bindings in the later version are indeed the same as PD-M515.

(edit; I checked and they are; the platform ('body plate') part Y41C-98011 is common between later versions of PD-M747 and PD-M515.

cheers
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~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~

zenitb
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Re: SPD pedal compendium

Postby zenitb » 26 Nov 2020, 12:20pm

Brucey wrote:FWIW it seems there are two different versions of the PD-M747 pedal. The first version has a thin rearward extension to the 'platform' which acts as a stopper plate for the rear jaw, and is the version I have photographed in my previous post. This 1995 techdoc shows the same arrangement.

Image

however the only techdoc on shimano's site for PD-M747 shows a later version with different parts in the mechanism, which is what zenitb appears to have.

https://si.shimano.com/api/publish/storage/pdf/en/ev/PD-M747/EV-PD-M747-1521B.pdf

so possibly the bindings in the later version are indeed the same as PD-M515.

(edit; I checked and they are; the platform ('body plate') part Y41C-98011 is common between later versions of PD-M747 and PD-M515.

cheers

Well that certainly explains it Brucey. Not only did they change the SM-SH51 cleat without changing the part number but they did it to the PD-M747 pedal as well !!!!!

The moral of this story seems to be "don't assume two Shimano parts with the same part numer are the same" !!!

(Great detective work BTW )

Brucey
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Re: SPD pedal compendium

Postby Brucey » 26 Nov 2020, 7:55pm

the good news is that you can rebuild your PD-M747s using a few jaw/platform parts salvaged from PD-M515 or similar. If I need spare parts for my PD-M747 pedals, it'll have to be a full set, else it won't be the same action on both sides of the same pedal even.... :roll:

I wonder how many other pedal models have been revised on the QT?

cheers
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~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~

zenitb
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Re: SPD pedal compendium

Postby zenitb » 27 Dec 2020, 12:09am

Brucey wrote:the good news is that you can rebuild your PD-M747s using a few jaw/platform parts salvaged from PD-M515 or similar.....
cheers

Ok I have now done what Brucey suggests above. I got given an old PD-M424 pedal where the goofy plastic pedals had broken off. Underneath this is simply a PD-M515 so its compatible with my late model PD-M747 "XT" pedal
P1050030.jpg
PD-M424 with plasic cages removed

Here is the broken jaw from my old XT pedal with the scavenged replacement part
P1050023.jpg
Replacement jaw with original broken part

I did notice that the "Made in Japan" XT pedals jaw plating had a different sheen to the cheaper PD-M424. The XT was a blue sheen whereas the cheaper pedal had a warmer tone - not sure that comes out in the picture though. Could the XT pedal have a better quality plating ?
Sheen comparison.JPG
More blue sheen on XT pedal jaw on left ?

The PD-M424 axles were compatible so I nicked those as well since the sleeves were not full of grit like my XT ones (I'll fix them later)
20201220_140805.jpg
Note chroming on XT axle, otherwise compatible.

In use on my bike .. 24 mile boxing day ride today, 18 years after last using the pedal. That's 3 out of 5 broken SPD pedals fixed so far :-)
2020-12-23 13.11.23.jpg
PD-M747 XT pedal back in use with scavenged parts

I have done a longer blog post on the repair here http://zenit-b.blogspot.com/2020/12/shi ... hment.html

Brucey
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Re: SPD pedal compendium

Postby Brucey » 27 Dec 2020, 12:17am

good work!

FWIW only the topmost (and thinnest) layer in chrome plate is actual chrome; most of the plating thickness is an underlying nickel layer, which is distinctly yellow in colour. Chrome plate varies slightly in colour anyway, but worn chrome plate is usually somewhat yellower in colour than unworn chrome plate, because the nickel shows through.

Also when SPD pedals feel 'gritty', most often this is just grit between the spindle and the plastic sleeve; it takes quite a lot of use in very adverse conditions for dirt to make it as far as the bearings themselves.

The usual service (which simply forces grease through the bearings as the pedal is reassembled) is normally more than enough to force grit out from between the spindle and the sleeve too, so full disassembly is not usually required. I'd certainly try that first, anyway.

cheers
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pwa
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Re: SPD pedal compendium

Postby pwa » 27 Dec 2020, 8:45am

That is one of the things I love about SPDs, the way you can do a lazy but effective re-grease by simply unscrewing the axle / bearing assembly, packing the body with new grease, then screwing the assembly back in (with force required) as you watch old grease escape past the seals like toothpaste. Very satisfying.

SPDs are one of the few things on a bike build that I don't give too much thought to. I don't need to think about an alternative. I did that once and it came back to bite me, so never again. The only question is "Which genuine Shimano SPD will it be?", single sided or double.