Sakae/Ringyo (SR) Roundtech (SR-307) NOS/NIB Vintage 50T 110 BCD Outer Chainring

Sakae/Ringyo (SR) Roundtech (SR-307) NOS/NIB Vintage 50T 110 BCD Outer ChainringOriginal part produced in the 1980s New old stock & still in the original packaging! Suitable for historic cycling events such as L'Eroica Worldwide shipping Sakae Ringyo (SR) Roundtech chainring (or chainwheel if you prefer), hailing from Japan and in production during the 1980s (yet still new & unused after all this time!). Made from aluminium and weighing in at 154 grams. A fine choice for keeping your vintage bike authentic, but also great for any

✓ Original part - produced in the 1980s
✓ New old stock & still in the original packaging!
✓ Suitable for historic cycling events such as L'Eroica
✓ Worldwide shipping

Sakae/Ringyo (SR) Roundtech chainring (or chainwheel if you prefer), hailing from Japan and in production during the 1980s (yet still new & unused after all this time!). Made from aluminium and weighing in at 154 grams. A fine choice for keeping your vintage bike authentic, but also great for any other compatible bike.

If you're taking part in L'Eroica, Anjou Velo, Velo Retro or another similar vintage cycling event, this is fully compliant - so rest assured, the pre-1987 police won't lock you up for having the wrong chainring!

OVERVIEW

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Condition - New Old Stock - In Original Packaging*
Model ID - SR-307
Production Era - 1980s
Country - Japanese
Material - Aluminium
Weight - 154 g
Stock Code - D-CRO63V

*New old stock items may have marks from storage over the years, and as we often have multiples they can vary from piece to piece, but they are always genuine new & unused items.

TECHNICAL INFO

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Tooth Count - 50
Between Adjacent Bolt Holes - 64.7 mm
BCD - 110 BCD
Bolt Count - 5-Bolt
Chain Width - 3/32" (Standard)
Intended Speed* - 5 Speed, 6 Speed, 7 Speed

▼SHIPPING, TAXES & RETURNS

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We've been safely sending orders around the world since 2010. There's a handy shipping calculator on the shopping cart page so you can see the cost of postage as soon as you've added it to your basket. Your order will be carefully packed and sent with tracking & insurance, we despatch most orders within 2-3 days but larger items and orders placed before the weekend can take an extra day or two to process.

We accept returns, please notify us within 14 days and ensure the item arrives back with us no later than 30 days after the order was received.

EU Customers – for orders under €150 (excluding shipping), VAT will be collected at checkout, but from 1st July 2026, due to new EU import regulations, there may also be a customs duty payable to the carrier. For orders over €150, all import fees will be payable to the carrier, with nothing collected at checkout.

USA Customers – import fees are now collected at checkout for all orders to the US, so there won’t be any surprise charges when your order arrives.

Other International Customers – local import fees may still apply, charged by your customs office or courier before delivery. These are not collected by us, so please check your local rates before purchasing.

Any applicable fees will appear at checkout.

▼HELP SECTION

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Tooth Count - the number of teeth on the chainring, the higher the number the harder the gear.

Between Adjacent Bolt Holes - the measurement from the centre of any bolt hole to the centre of an adjacent one, if this measurement is the same as that of your crankset and the bolt count is the same then the chainring should fit.

BCD - stands for Bolt Circle Diameter (sometimes referred to as PCD - Pitch Circle Diameter) and is the technical way to determine whether the chainring fits your crankset. To calculate, multiply the distance between adjacent holes (in mm) by 1.709 (you’ll likely need to round the resulting number up or down a little).

Bolt Count - the number of bolts securing the chainring to the chainset. As with the BCD, this must be the same as your chainset.

Chain Width - 3/32” is the standard width for double and triple chainsets, wherease 1/8” chainrings are only found on single ring chainsets, generally for track / singlespeed use and can only be used with a wide 1/8" chain.

Intended Speed - the number of cogs at the back the chainring was designed to be used with. We refer to it as ‘intended’ speed as most double and triple chainsets will actually work with different speeds than originally intended, but the further away you get from the intended speed the more likely you are to experience minor setup issues. The exception being some chainrings intended for 10 speed use or higher, with these it’s better to stick to the intended speed.