Shimano Dura-Ace (GB-100) 1st Gen c.1972/73 Vintage English 112 mm Bottom Bracket

Shimano Dura-Ace (GB-100) 1st Gen c.1972/73 Vintage English 112 mm Bottom BracketOriginal part produced in the 1970s Suitable for historic cycling events such as L'Eroica Professionally checked & cleaned Worldwide shipping Shimano Dura Ace bottom bracket (or BB for short), hailing from Japan and dating back to 1972 73. Made from steel and weighing in at 295 grams pretty lightweight for a BB at that time. A fine choice for keeping your vintage bike authentic, but also great for any other compatible bike. When the Dura Ace 7100

✓ Original part - produced in the 1970s
✓ Suitable for historic cycling events such as L'Eroica
✓ Professionally checked & cleaned
✓ Worldwide shipping

Shimano Dura-Ace bottom bracket (or BB for short), hailing from Japan and dating back to 1972/73. Made from steel and weighing in at 295 grams - pretty lightweight for a BB at that time. A fine choice for keeping your vintage bike authentic, but also great for any other compatible bike.

When the Dura-Ace 7100 series was introduced in the 1980s the bottom bracket spec didn't change, so the GB-100 bottom brackets are compatible with both the earlier GA-200 / GA-300 series as well as the later FC-7100, as long as the axle length is correct.

If you're taking part in L'Eroica or a similar vintage event, this is fully compliant - so rest assured, the pre-1987 police won't lock you up for having the wrong bottom bracket!

The bottom bracket's been carefully cleaned, thoroughly checked by one of our mechanics and graded as OK condition, but do take a good look at the detailed photos so you can see the cosmetic condition before you buy.

OVERVIEW

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Bearing / Race Condition - OK
Model ID - GB-100
Production Era - 1970s
Country - Japanese
Material - Steel
Weight - 295 g
Stock Code - U-G3-BB199V

TECHNICAL INFO

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Thread Type - English Thread (British/ISO 1.37" x 24 TPI)
Axle Length - 112 mm
Axle Type - Square Taper
Compatible Chainset(s) - Shimano - Dura-Ace GA-200, GA-210, GA-300, FC-7100, FC-7110

▼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.

▼SAFETY & COMPLIANCE

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This product complies with the EU General Product Safety Regulation (GPSR). Professional installation and regular inspections are recommended. Due to the product's age, extra care should be taken during use.

Product Manufacturer - Shimano Inc. 3-77 Oimatsu-cho, Sakai-ku, Sakai-shi, Osaka 590-8577, Japan

EU Authorised Representative - Global Trade Department NI Ltd, Office 834, Unit 6, 100 Lisburn Road, Belfast BT9 6AG, Northern Ireland

▼HELP SECTION

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Thread Type - this must match the bottom bracket thread on your frame. The 3 common thread types on classic and vintage bikes are English (also known as British or ISO), Italian & French, and are usually (not always!) found on frames built in their respective countries. If you're replacing a bottom bracket the cups should have the thread type stamped on one of them, if not there are a couple of things to look at; bottom bracket shell width (English & French = 68 mm, Italian = 70 mm) & drive side cup thread direction (English = left, Italian & French = right). The only curveball to watch out for here, although pretty uncommon, are Swiss threads (also found on some French frames, Motobecanes being one) which will have the same shell width & thread direction as an English thread frame but the actual thread pitch will be different. If none of the above matches what you have, there are a few lesser known varieties that will require some further research.

Axle Length - your crankset dictates the axle length you need and the recommendation should be used to avoid issues with chainline. If you're replacing a bottom bracket that works perfectly then this can be matched, otherwise you'll need to check the manufacturers spec, a good resource for older bikes is Velobase.

Axle Type - you can tell which type of axle you need by looking at the shape of the bottom bracket hole in your crankset. For square tapers, the ISO introduced a standard for European makers in the early 90s, JIS then did the same in Asia. Before then it was not so simple, and although there is a degree of interchangeability, the best way to make sure you have the right axle is to stick to the same brand from the same era, ideally the proprietary model.