The Chainlink

MDI - Meidai Bicycle Pumps: Do you have one and do you love it?

  I've stumbled on a topic which no one has posted and for which there is very little information elsewhere. There is no question people love their Silca, SKS, TopeakPark Tool, Lezyne, or other favorite brand pumps but let's lend a little focus to a defunct brand which sold many bike pumps to American consumers and which have served us well for years and years.  I'm doing some maintenance on mine, such as adjusting, cleaning, and installing replacement parts, so I felt inspired enough to document the process.

  MDI sold pumps under the Cyclepro name and that is what I have had since about 1994, and it's otherwise known as the Meidai Top Super.  Please note:  This also applies to MDI manufactured Schwinn and Rampar branded pumps!  The maximum pressure (on the gauge dial) for these pumps is 140 PSI, which is enough for everyone who has "clincher" tires, but I've pumped up tubeless Tufo tires to 180 PSI with it.  It has survived weekly or biweekly sessions of pumping up tires through thousands of miles on my various bikes.  I have never changed the pump washer or tube washer until now.  I haven't needed anything to maintain it, except a little lube, until now.  The cylinder walls are still thick and intact despite all of the fillings and refillings of my tires through the years.  It has put up with neglect in various basements, survived crashing to the floor countless times, and it has put up with my overwhelming zeal for cycling.

  Simply stated, my MDI/Meidai Top Super bicycle pump is a rock solid tank which just needs a little TLC to keep going.  Here are the components I'm considering this week to keep my pump in shape for the next 20 years:

  I am still hanging on to my old MDI thumb lock air chuck as it still works just fine.  Also, after rebuilding the head with a new valve washer and housing it works like it did when it was new, losing at the most 5 PSI when compared to a hand held gauge.  I've had an original brass SILCA Italian made classic style presta head in my tool box for many years and when attached to the MDI air chuck it works effortlessly.

  Bypassing a full overhaul, the easiest thing to do is simply replace the hose and hose barb and to maintain the original internal hose diameter - (as of 8/6/2017 I concede I've found the right tubing on McMaster Carr for $0.60 per foot) 3/16" ID 250 PSI tubing by the foot, 7/16" OD, Thermoid VALUFLEX/GS McMaster SKU 5304K42 with Oetiker hose clamps McMaster SKU 5435K12- makes the Silca 3/16" tube kit with clamps look like a bargain for one pump but expensive for two.  See the link below for the hose barb to make 3/16" hose work on your MDI - the original hose barb just isn't long enough for hose clamps to really keep the hose from falling off the pump. The original MDI hose only worked because a fitting was crimped to the end of the hose by a specially built machine at the factory in Japan.  Since this fitting is brass, be sure to use a little grease on the threads before screwing it into the pump base and be certain to keep the pump away from water or damp areas - if kept wet the brass fitting will seize and rust into the base and you won't be able to get it out or replace it. You may also be able to find this at your local hardware store, Menards, etc. Dynaflo 3/16" Hose x 1/8" Male NPT Brass Hose Barb, for up to 150 PSI applications, Fastenal SKU 69918, UNSPSC 40141734, comes in pack of 5, $3.80 per pack, $9.61 shipping.  Personally I moved to having both 3/16" and 1/4" hose and accessories on hand...but (as of 8/6/2017) I've also employed a method of attaching and detaching these with reliable, relative ease.

  MDI was forward thinking enough to allow their customers to easily access the pressure gauge dial face for adjustments.  Two screws are taken out and you are there.  With a small screwdriver (1/8" wide slotted head) and a Post-It note protecting the dial face one can gently pop off the needle and readjust it to zero.  There is no threading or retaining nut keeping the needle on, it's just a very solid friction fit like the minute hand on a clock.  I adjusted mine and it is reading PSI and Bars accurately as compared to my two tire gauges which I recently had calibrated by G.H. Meiser (under their amazing and wonderful lifetime warranty!).

  Thankfully Silca has the pump washer and lubricant that appears most appropriate for this maintenance project.  I'm quite certain it will work, but I'll repost when everything is installed.  I could keep going with the original MDI pump washer but I'd rather replace it now before it falls apart.

  As I said at the beginning of this article, my caveat about these pumps is of course that the company no longer exists.  However I am bolstered by my research.  G.H. Meiser in Posen, IL said they would take a look at it if I sent it in for service as well, but fortunately this is not necessary.  

Please let me know if you have any information or critique about this project.


Matt M

"I'm sure there's a crying need for that."

- Mrs. Hudson, Sherlock, The Empty Hearse, 2014

(P.S. Several Ebay auctions are active for MDI/Meidai pumps. If you would like to investigate further also look for Rampar and Schwinn 1500.)

Please note that  I am not liable or responsible for any repair to any pump you may attempt as a result of the recommendations of this article.  You will be relying on your skills and expertise for your various projects.  Please be safe and take the necessary precautions that all of your pneumatic connections are secure for high pressure applications.

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The rabbit hole is deep, my friends - here is a pump which can inflate things to 4500 PSI - a Taousa Airgun PCP Pump...inflates on the up and down stroke.  New pressure gauges can be swapped in to the base.

An intriguing idea from Milan (Italy) - the Sapo One Professional for all valve types to 230 PSI.  Really looks fantastic.  Inflates Presta, Schrader, Regina, and Dunlop.  I don't own a bike shop but I want this pump!  Sapo's main website is here.

I finally found an inexpensive but well made close relative to the Continental Tubing from SILCA - - 3/16" ID 250 PSI tubing sold at $0.60 per foot, 7/16" OD, Thermoid VALUFLEX/GS McMaster SKU 5304K42  - made in Ohio, USA.  These dimensions are identical to the tubing in SILCA's kit.  I edited the discussion heading above to reflect this discovery (or rediscovery because I just don't remember if I saw it when I started the discussion / project).  I doubt you'll find anything else close to it or better than Thermoid Valuflex unless you order through SILCA.

"Hello - - - I fully investigated all options for repairing my CyclePro MDI - please see my article on The Chainlink - [U]MDI - Meidai Bicycle Pumps: Do you have one and do you love it?[/U]. Here is the short version: Threading for the pump hose to the base is 9.5mm coarse thread (according to Yellow Jersey) but 1/8" NPT pipe threading works fine and does not cross-thread, strip out, or loosen when tightened. You can find 1/8" NPT threaded hose barbs, pipe, etc. at many hardware stores, Home Depot, etc.

If the Pyramid / Sunlite Model M / Yellow Jersey after market replacement hoses aren't a good match for you, or simply too cheaply made, you can step up to Silca's Replacement Hose with clamps kit with 3/16" inside diameter and 7/16" outside diameter or to HBD Thermoid VALUFLEX/GS rated at 250 PSI with 3/16" inside diameter and 7/16" outside diameter from McMaster Carr (item # 5304K42). In order to use Silca's kit or the Valuflex tubing you need to upgrade your hose barb to make sure the hose stays put on the pump - this can be a 3/16" hose X 1/8" NPT steel barb or stainless steel barb. You may also use a 3/16" hose X 1/8" NPT brass hose barb to connect to the pump base but you have to keep it away from moisture and grease the threads before installation because brass connected to steel will rust. If you decide against Silca's kit and purchase the Valuflex tubing instead, be sure to purchase Oetiker stainless steel clamps (known also as pinch clamps and ear clamps) McMaster Carr (item # 5435K12) .

Lastly, if the head of the hose where you attach the valve isn't working you may replace it with a variety of options available from Silca or other manufacturers, but if you want to hang on to the original MDI part you may rebuild it with parts from other hoses. I used the head from Monarch Bicycles on Ebay; the item number for this hose on Ebay always changes but the auction title is always the same "Bicycle Pump Hose 24" Steel Thumb Lock Schrader Hose NEW!" (Monarch is not currently selling on Ebay, though...) . The "Sunlite Universal Thumb Lock Hose End" on Amazon item number B00629RMZE is a bit cheaper and it's likely you only really need the washer in the head (which clamps on to your tire valve) and perhaps the housing to keep your old MDI head going - I haven't tried it but for $6.25 and free shipping it seems like it's worth a try.

But there are some advantages to moving to 1/4" inside diameter hose since that is most common in auto shops. The following from Lumiteco is a 1/4" inside diameter hose head with steel thumb lock is item B076F2PL5H " 1/4"Lock On All Metal Air Chuck,Mini Air Compressor Portable Tire Inflator Tire Chuck, Hose End with Barb Connector for Hose Repair Inflate Chuck--2Pack". It may be the Lumiteco head also has all the parts you need, save for the 1/4" barb, to repair your MDI head. Also I have become a huge fan of the air chucks with steel lock for 1/4" from Interstate Pneumatics (specifically the T02 - Amazon item B011LBZQ7I ) since it works beautifully with my Presta head from Silca resulting in no pressure loss on my MDI bicycle pump. Bear in mind that moving to 1/4" hose means you need a 1/4" hose barb and slightly larger pinch or ear clamps unless you are happy with getting standard hose clamps from the hardware store.

As far as the leather pump washer, or "cup packing", which is housed inside the cylinder of your pump (it's what puts air through the pressure gauge and the pump hose), there are a couple of options as discussed in BikeForums and elsewhere. 1. (This first one is from my article on The Chainlink) Buy one from Silca - it's could be the Silca 741 (30mm diameter) but measure your pump cylinder before you order (the dimension for my MDI pump cylinder is 29.8mm and I am using the Silca 741 - it's great). 2. Find one somewhere- - sometimes they show up on Ebay. 3. Contact Monarch-McLaren, Ltd. in Wisconsin and have them make a couple of them for more than you probably care to pay. 4. Make your own- you might learn a new skill! You MUST use Silca's Pump Blood to install a new pump washer or it will crack and become useless. I also think a combination of leather conditioner and some light oil would do as people have been using this solution for many years. Clearly no lubricant which will clog the pump's airways should ever be used to install the pump washer.

Happy Cycling,

Matt M"

I really think this is my last post on the Chainlink for MDI pumps.  On the left (at 92mm mark) in the photo above is my original MDI hose barb. In the middle (at 113mm center mark) is an "Action" replacement hose threading. On the right (at 130mm mark) is an 1/8" NPT swivel connector for pipe. My original MDI barb still works on my pump after using the 1/8" NPT connector for over a year (as does the entire assembly). Please use the metric ruler for reference. If the "Action" replacement hose threading works on an MDI pump, please let me know which one it will fit on. There are two MDI Top Super pumps in a local bike shop near my home which also have the same threading as mine and this leads me to believe the "Action" replacement hose is not appropriate for many MDI bicycle pumps.

Additional information from the past few days:

From BikeForums - the Topeak Smarthead Upgrade kit. Will it work??? We would all like to know. I considered purchasing this at the beginning of my project in 2016, but I decided that the Topeak would not be as nice as having my MDI thumblock back, especially when combined with a Silca presta chuck.

If you are fighting with your MDI because it doesn't hold air either the air check valve has failed in your pump (which is something I'm not even sure really exists) or your hose has some kind of issue. I suppose a VIAIR 92823 check valve might be a solution to the problem but this is something I'm still investigating (it's the one with the red thread compound on it).

Anyone know if replacement rubber for the head is available anywhere? There is a picture of it below. Thank you.

Just get a new thumb lock hose and swap in the washer.  Ebay Item 232988258580.  Worked great on mine: this is exactly the same part I used.

...there might be a small height difference between the old and new washer though.....swapping on the new housing will fix this....or just use the new chuck...the new hose is really trash.

Hi Matt, I'm revisiting this post as I recently found a Medai at a thrift store I'm going to rebuild, and I'd love your feedback as you seem to have developed a serious expertise about these pumps! I sent you a private message. I also have an SKS I purchased this fall for $15- based on my research it's over 50 years old and still going! Same thing as the Medai, I'm going to rebuild as well- new hose, repaint the base, etc. 

The Medai is going to need a new hose, and I am going to try to either run a pressure gauge off the base bar threat with a t-junction, or maybe even drill, tap, and run one on top of the overflow canister. Either way, I'd appreciate your advice!

Sorry....not on here much anymore... I just stuck one in-line on the hose itself with a brass T.  The connection is solid but of course I went nuts and put a huge easy to read 200 PSI industrial gauge on because I have been squinting to see the numbers on bike pump pressure gauges since I was 10 - and I have never really needed glasses or even reading glasses.  You know what I mean.

As far as the overflow canister - I just left it alone.  I never moved past that point.  I really wanted to get my hands on more than my pump in the photos also but I never got further than that either.

Really nice choice with the Meidai Top Super!!  Use the NPT threading I quoted if you want to get fancy with a new hose barb (which I'm almost certain should work - but carefully thread the barb in before you tighten it down) and the Thermoid Valuflex or any 1/4" air hose.

Good luck and have fun!

A quarter century old....walked away from the pump 5 minutes ago and not losing air.  I actually put a bleed valve on.  Enjoy!



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