Author Topic: Wienman centrepull ugrade/ help  (Read 2481 times)

Wienman centrepull ugrade/ help
« on: 19 September, 2017, 09:26:53 am »
Morning all, I'm slowly bring my 86 Raleigh Granada touring bike into action, I've swapped the drop bars for some butterfly ones as years of mtb sees me and my aging back preferring the upright position.
My issue is the aging and original centrepull brakes, not inspiring confidence and matched with some little variants brake levers the don't seem to the the (or any) oomph, and this is before I fully load the old girl.
I don't have any fork lug/ bosses and guess this will limit my options, it is also a fairly long drop as have good mudguard. Clearance.
Please help me rethink my braking issues- meagre/ modest budget.

Re: Wienman centrepull ugrade/ help
« Reply #1 on: 19 September, 2017, 09:39:44 am »
important; these brakes will not work well with brake levers meant for 'V' brakes, or even the latest DPs. You need levers with a short cable pull, like old weinmann, diacompe etc. A modern alternative may be the levers sold by velo orange.

Also;

- use good quality brake blocks eg ones for V brakes, eg clarks gold
- set the brake block spacing so that the caliper is only just wide enough (with the cable disconnected) to let the rim through; this will give the best mechanical advantage to the brake
- use new cables and housings. Lined housings with suitable lubricant and polished stainless steel inners

If your rims are chromed steel, you will be able to make them work OK in the dry but they will always be poor in the wet.

If they are set up OK the weinmann CPs are pretty good brakes. I'm sure that some folk will suggest that you ditch them for DPs but they are perhaps missing the point, on a retro bike.

cheers

Re: Wienman centrepull ugrade/ help
« Reply #2 on: 19 September, 2017, 12:49:02 pm »
Thanks Brucey, all helpful. Excuse my ignorance but what is DP short for? My old wienman always pulled up in the past so maybe life in the old dogs yet, will pay with blocks and look into levers.

Re: Wienman centrepull ugrade/ help
« Reply #3 on: 19 September, 2017, 01:25:01 pm »
DP = dual pivot (brakes)

cheers


Re: Wienman centrepull ugrade/ help
« Reply #5 on: 19 September, 2017, 03:47:14 pm »
Thank you Brucey and Karla

Torslanda

  • Professional Gobshite
  • Just a tart for retro kit . . .
    • John's Bikes
Re: Wienman centrepull ugrade/ help
« Reply #6 on: 19 September, 2017, 06:45:31 pm »
Hi Shack, my thoughts as follows.

If you have Weinmann centre pulls they will have a red label 'Vainquer 999'. Pay attention to the branding, the number will give you the brake drop. Weinmann 750 (usually the rear) =max drop 75mm, 610 = 61mm. If you want to replace them with dual pivots these dimensions are vital.

You mention butterfly bars, I'm assuming that you will have changed the brake levers. These need to have the same cable pull as your old drop bar levers because modern  v-brakes pull more cable. They will work but will feel wooden and VERY weak. Fear not, many brands are available and finding them isn't difficult.

What was said upthread about wheel rims is pertinent too. No matter how good you thought the brakes were I can guarantee that compared to modern stuff centre pulls on steel rims are scary! In the wet you have to write them a letter...  But before yo bin them change the rims if that's what you have.

Happy to help if I can

luv'n'stuff

J
VELOMANCER

Well that's the more blunt way of putting it but as usual he's dead right.

Re: Wienman centrepull ugrade/ help
« Reply #7 on: 19 September, 2017, 09:34:33 pm »
Thanks J,  all very interesting I will pop out tomorrow and have a good look see in daylight. If I end up going back to drop bars it isn't the end of the world I've kept my levers and the van ones are very cheap halfords jobbies ( fitted but bike was on a trainer in garage so never actually. Used)
Does anyone know if I'm likely to get a compatible. Adjustable stem for my aged original current quil ( I think)

Torslanda

  • Professional Gobshite
  • Just a tart for retro kit . . .
    • John's Bikes
Re: Wienman centrepull ugrade/ help
« Reply #8 on: 19 September, 2017, 10:57:10 pm »
Yes. Easily.
VELOMANCER

Well that's the more blunt way of putting it but as usual he's dead right.

rogerzilla

  • When n+1 gets out of hand
Re: Wienman centrepull ugrade/ help
« Reply #9 on: 20 September, 2017, 06:42:08 am »
Dia -Compe make better (stiffer) new centre-pulls; they work better than dual-pivots or side-pulls when the reach is prodigious, although they are heavy, have a rather exaggerated pad sweep and a sub-optimal reduction of mechanical advantage as the pads move closer to the rim (like cantilevers).

However, new pads and cables and getting the arms as wide as possible will improve the power of the Weinmanns.
Hard work sometimes pays off in the end, but laziness ALWAYS pays off NOW.

Re: Wienman centrepull ugrade/ help
« Reply #10 on: 20 September, 2017, 09:34:19 pm »
So rogerzilla are you saying the reach is too far because my new levers are designed for v brakes? And in your opinion new stiffer centre pulls would be better than DP or side pull?  what would you suggest with fetter levers (or suggest for levers)
FYI my rims are mavic ma2 from memory

Torslanda

  • Professional Gobshite
  • Just a tart for retro kit . . .
    • John's Bikes
Re: Wienman centrepull ugrade/ help
« Reply #11 on: 20 September, 2017, 11:12:51 pm »
I think you might be getting a tad confuzzled.

'Reach' or 'drop' is the distance from the brake mounting bolt to the bottom of the slot in the brake caliper, ie the maximum. If the brakes and wheels are the originals you have no need to think about them.

The difference between canti & v-brake levers is the distance between the lever pivot and the cable attachment point. V-brake levers have the attachment further away from the pivot, hence they 'pull more cable' ove rthe same arc travel. Some brake levers have a movable cable attachment. If you're interested I can measure a couple of different sets tomorrow and let you know.

MA2 rims are a tad on the narrow side for Weinmanns. As the pads wear the mounting face of the arms obviously get closer in. What Roger is saying is the closer the mounting faces becomes the more the stopping power is reduced. If the caliper arms move in beyond vertical the straddle cable stops pulling 'in' and starts pulling 'up' instead, so thicker pads will ensure this doesn't happen. You can make the pads thicker by using a washer between the pad and the caliper arm at a pinch but a different pad - such as the cartridge type seen on modern dual pivot brakes may be thicker than the original 80s types. I've got both kinds in stock, I'll have a weigh up tomorrow.

Conclusion. If your pads are worn and you're using v-brake levers there's a very high probability that your brakes will be crap.

HTH

John
VELOMANCER

Well that's the more blunt way of putting it but as usual he's dead right.

Re: Weinman centrepull ugrade/ help
« Reply #12 on: 21 September, 2017, 06:01:08 am »


Weinmann 610 centrepull, fitted with cartridge type V-blocks and non-standard mounting nuts etc., MA2 rim.

The spacing of the brake blocks is as per my earlier post, i.e. so that the caliper only opens a little wider than the rim. To make this work as well as possible, I machined the bases of some domed nuts, so that they replaced one of the concave washers in the standard mounting. I also added some washers where the brake block bears against the brake arms; the curved washers are small diameter and the slot in the arms is of a generous width, which didn't seem quite right without such washers. If you don't need to adjust the toe-in, a simpler arrangement of spacers is possible.

These calipers are paired with weinmann non-aero dropped bar brake levers but some shimano ones (that originally were used with side-pulls, rather than DPs) will also work well if you want an aero lever.  There are flat bar levers that have the correct MA for using with this type of caliper too.

These brakes are good; as good as a rim brake gets, pretty much.

cheers

Re: Wienman centrepull ugrade/ help
« Reply #13 on: 21 September, 2017, 09:19:37 am »
Thanks Brucey etc Al, it's like being back at school (but in a good way) I have new cartridge pads and the calipers are 610's, and all feeling pretty well dialled in/ adjusted,  so I'm guessing it's those brake levers of mine are the weak point in my set up, I'm happy you ugrade one of my daughters bikes with them as they have nasty plastic and very budget affairs ( but they are v-brakes at least)

Torslanda

  • Professional Gobshite
  • Just a tart for retro kit . . .
    • John's Bikes
Re: Wienman centrepull ugrade/ help
« Reply #14 on: 21 September, 2017, 09:35:40 am »
If you have inline adjusters I have a very swish looking pair of Tektro levers that have the correct pivot.
VELOMANCER

Well that's the more blunt way of putting it but as usual he's dead right.

Re: Wienman centrepull ugrade/ help
« Reply #15 on: 21 September, 2017, 09:40:35 am »
Which ones are those Tors? I've always found it a right pain to work out which ones are correct - the Tektro documents don't always publish the pull ratio.

Re: Wienman centrepull ugrade/ help
« Reply #16 on: 21 September, 2017, 10:47:30 am »
the Tektro levers for dropped bars that I have seen are suitable for DPs and won't give full power if used with CPs. CPs work best with a lever that is about 4:1 MA and few modern drop bar levers come close to that (most that are meant for current DPs are 3-and bit :1. Ones for older DPs (roughly all new models of shimano DP/lever launched before 2008) are better than that but usually still not quite  the full whack through the whole stroke.

Some (not all) flat bar levers that are meant for cantis have about 4:1 MA and get the best out of CPs too. Not sure if any Tektro ones are like this.

cheers

rogerzilla

  • When n+1 gets out of hand
Re: Wienman centrepull ugrade/ help
« Reply #17 on: 22 September, 2017, 03:45:17 pm »
I'm using Dia-Compe 188 levers with cemtre-pulls.  They feel like they should do.  Useful for bullhorns or straight bars (188s are actually designed for straight bars on Chinese utility bikes).
Hard work sometimes pays off in the end, but laziness ALWAYS pays off NOW.